TROUBLESHOOTING

A drive doesn’t appear

Problem

You’ve plugged in a USB stick or SD card, but it isn’t in DiskSnap’s list.

Likely cause

Windows hasn’t detected it yet, the port or reader isn’t working, or the card isn’t fully inserted. DiskSnap can only list drives that Windows can see.

What to do

1. Wait a few seconds. DiskSnap refreshes by itself when a drive is plugged in. Or press Refresh.
2. Try another USB port, one directly on the PC rather than a hub, dock or extension cable.
3. For an SD card, push it fully in. An empty card reader shows as No media detected — insert a card.
4. Check whether Windows sees it: right-click Start and open Disk Management. If the drive isn’t there either, the problem is the drive, reader or port, not DiskSnap.

A drive is shown but locked (including “Protected — Windows system disk”)

Problem

The drive card is greyed out with a padlock and a reason, and you can’t select it.

Likely cause

DiskSnap is protecting it. The reason on the card says why.

What to do

Reason on the card	What it means
Protected — Windows system disk, Windows boot disk, Windows is installed on C:	That’s your PC’s own drive. DiskSnap will never use it. Working as intended.
Protected — internal NVMe drive (or SATA, and so on), virtual disk, unknown connection type	Only USB sticks and SD cards can be used. Internal drives, mounted disk images and unrecognised drives are always locked.
No media detected — insert a card	A card reader with no card in it.
Drive is offline in Windows	Windows has taken the drive offline. After a clone, see A cloned drive goes offline.
Drive is write-protected	It can be read but not written. For an SD card, slide the lock switch on its side (or on the adapter) away from “Lock”, then remove and reinsert it.
Protected — DiskSnap is running from this drive, your DiskSnap backup folder is on this drive	Erasing it would erase DiskSnap or your backups. Use another drive, or change the backup folder in Settings.
Protected — the selected image / backup is stored on this drive	The file you’re writing from lives on that drive. Copy the file to your PC first, then choose it again.
This is the source drive	Clone only: you chose it as the source, so it can’t also be the target.
Too small for this backup / Too small to clone the source onto	See The target is too small.

Important

These locks can’t be switched off, and that’s deliberate. There’s no setting that lets DiskSnap write to an internal or Windows drive.

“No usable SD cards or USB drives found”, but drives are plugged in

Problem

The list says no usable drives were found, or shows only locked ones.

Likely cause

Every connected drive is locked for this job. On the Clone page this also happens when the source is larger than every other drive, so none can be a target. The wording is a known cosmetic issue.

What to do

Read the reasons on the locked cards (above). For Clone, use a target at least as large as the source.

You think you’ve selected the wrong drive

Problem

You’re not sure the selected target is the drive you meant to erase, or you realise you picked the wrong one.

Likely cause

Two drives look alike, or more removable drives are connected than you expected.

What to do

1. If you haven’t confirmed yet: click Cancel in the confirmation box. Nothing has been touched.
2. Unplug every removable drive except the ones this job needs.
3. Compare the serial number (S/N) on the drive card with the one in the confirmation box. It’s the most reliable way to tell two drives apart.
4. If the operation is already running on the wrong drive: press Cancel in the progress window straight away and confirm.

Important

If DiskSnap had already started preparing or writing the wrong drive, its previous contents are gone. Don’t write anything else to it: if the data matters, a data recovery service may be able to get some of it back, and every further write makes that less likely. DiskSnap can’t undo a write.

Two drives look identical

Problem

Two sticks or cards have the same name and size, and you can’t tell which is which.

Likely cause

Same make and model. Windows gives them the same name.

What to do

1. Go by the serial number on each drive card, not the name or disk number.
2. Still unsure? Unplug one, and see which card disappears.
3. Label them physically before you start.

Important

The Clone confirmation shows both serial numbers where reported. Match both drives before confirming; do not rely on disk numbers from a previous session.

Windows blocks the installer or app

Check that the installer came from the official download page. Record the exact Windows security message: Smart App Control and other protections may prevent an application from running.

Do not disable Windows security to get past a block. Stop and retain the message, Windows version and installer filename for support.

DiskSnap asks for administrator permission

Problem

When you start an operation, DiskSnap says it needs administrator rights and offers to restart, then Windows asks Do you want to allow this app to make changes to your device?

Likely cause

Normal. Windows only lets administrators read or write a whole drive. DiskSnap starts without these rights and only asks when you actually start an operation.

What to do

1. Say yes to DiskSnap’s question, then Yes to the Windows prompt.
2. DiskSnap reopens on the same page, with ADMINISTRATOR in the bottom-right corner. Your image or backup file (or Backup’s save folder) is kept.
3. Choose the drive again. That’s deliberate: drive numbers can change, so DiskSnap never carries a drive choice across a restart. For Clone, choose both drives again.

Important

If you say no to the Windows prompt, nothing happens and DiskSnap carries on as before; it just can’t run the operation. If your account can’t approve the prompt (common on work PCs), you’ll need someone with an administrator account. Follow your organisation’s administrator policy.

“DiskSnap is already running”

Problem

You try to open DiskSnap and get this message.

Likely cause

Another copy is open, perhaps minimised or behind other windows. Only one copy can run at a time, so two can never work on the same drive.

What to do

Find the open copy on the taskbar and use that. If an operation is running in it, let it finish.

It stops straight away: “… Nothing was written.”

Problem

You confirmed, and it stopped at once with a message ending Nothing was written (or Nothing was copied for Backup). For example: The drives connected to this PC changed since you made your selection, “…” is no longer connected, or DiskSnap will not write to this drive: …

Likely cause

Just before starting, DiskSnap re-checks that the drive is still the same one, in the same place, with the same size. Something changed, so it refused.

What to do

1. Check the drives are plugged in and haven’t been swapped.
2. Press Refresh, choose the drive again, and start again.

Important

Nothing was written means exactly that: DiskSnap stopped before changing the drive. It only uses those words when that’s true.

The target is too small

Problem

The drive you want to write to is locked as Too small for this backup or Too small to clone the source onto, or Make Bootable says Choose a larger drive.

Likely cause

Restore and Clone need a target at least as large as the whole original drive, not just the space that was used. Two drives sold as the same size are often a little different, so even a “32 GB” stick can be too small for another “32 GB” stick’s backup.

What to do

Use a larger drive. DiskSnap shows the exact size it needs. The manual explains drive sizes.

Important

Restoring or cloning to a smaller drive isn’t supported yet, even if the original was mostly empty.

“…-byte sectors… won’t restore / clone onto this drive”

Problem

DiskSnap refuses a drive because its sector size differs from the original’s.

Likely cause

A sector is the smallest block a drive stores. Almost every USB stick and SD card uses 512 bytes, but some larger drives use 4096. Partitions from one wouldn’t line up on the other.

What to do

Use a different target drive. There’s no override. Nothing was written.

A backup file can’t be opened: “This file can’t be restored”

Problem

After choosing a .dsnap file on the Restore page, DiskSnap shows ✖ This file can’t be restored. with a reason.

Likely cause

The file is incomplete (for example, a copy that didn’t finish), damaged, not a DiskSnap backup, or made by a newer version of DiskSnap (This backup was made by a newer version of DiskSnap…).

What to do

1. Read the reason shown underneath.
2. If you have another copy of the backup (on another drive or in cloud storage), try that one.
3. If the file was copied recently, copy it again from the original and check the copy finished.
4. For a newer-version backup, update DiskSnap.

Important

Nothing has been erased. DiskSnap checks the whole backup before touching any drive, so a damaged backup can never wipe your drive. A file ending .dsnap.partial is an unfinished backup and can’t be restored.

Restore won’t begin

Problem

The Restore… button stays disabled, or the restore stops before writing.

Likely cause

One of: no backup chosen or the backup failed its check; no target chosen; the target is locked (too small, holds the backup file, write-protected); the backup file was changed or moved after you chose it (The backup file has changed or been moved since it was checked. DiskSnap will check it again.); or the full backup check at the start found a problem (The backup file is damaged and can’t be restored).

What to do

Read the line at the bottom of the page: it says what’s missing. Then follow the matching entry: backup file, locked drive, too small.

Important

If the backup fails its full check when the restore starts, nothing is erased.

Clone won’t begin

Problem

The Clone… button stays disabled, or the clone stops before copying.

Likely cause

The source and target are the same drive (A drive can’t be cloned onto itself), the target is too small or has a different sector size, the source reports no data (no media?, usually an empty card reader), or one of the drives changed after you chose it.

What to do

Read the line at the bottom of the Clone page and the reason on any locked card. Choose the source first, then a target at least as large. After an administrator restart, choose both drives again.

Make Bootable won’t accept an image

Problem

After choosing a file, Make Bootable says it can’t be used.

Likely cause

DiskSnap looks inside the file and refuses anything it can’t turn into a working bootable drive. The message says which: an incomplete download (This ISO is incomplete…, Damaged or incomplete .xz file), an archive that needs extracting first (ZIP, 7-Zip, RAR), a CD/DVD-only ISO that can’t boot from USB, a single-partition image, or a file it doesn’t recognise.

What to do

Follow the message: download the file again from its official source, or extract the .img or .iso from the archive and choose that.

Important

Use an image compatible with your destination computer and obtain it from its official publisher.

“Another program is using the drive”

Problem

DiskSnap stops with this message.

Likely cause

DiskSnap locks a drive before working on it, so nothing can change it mid-way. It can’t while a window or program has files on it open.

What to do

Close File Explorer windows showing the drive, and anything else using it (photo importers, media players, antivirus scans), then try again. For Backup, also wait for any file copying to or from the drive to finish.

Backup warns about the save location

Problem

Backup won’t save where you chose, or warns before starting.

Likely cause

The folder is on the drive being backed up (not allowed), the location uses FAT32 (can’t hold files over 4 GB), or it has less free space than the drive’s size (the backup may still fit once blank space is left out and the rest compressed).

What to do

Choose a folder on your PC’s own drive, or an NTFS or exFAT drive with plenty of space. If you go ahead with a warning and space runs out, DiskSnap stops and deletes the unfinished file.

Important

Backup never changes the drive being backed up, even when it fails.

Very slow write or copy speeds

Problem

The speed shown is only a few MB per second, and the time left is long.

Likely cause

Usually the drive itself. Many inexpensive USB sticks and SD cards read reasonably quickly but write slowly, and some slow down further once their internal cache fills. A USB 2 port, a hub or a slow card reader also limits speed. Whole-drive copies and read-back verification can take a considerable time.

What to do

1. Let it finish. Slow isn’t the same as broken.
2. Next time, use a USB 3 port (often blue inside) directly on the PC.
3. For regular use, a faster stick or card makes the biggest difference.

Important

Don’t unplug a drive to “speed things up”. It leaves the target incomplete.

Progress appears stuck

Problem

The progress bar or percentage doesn’t seem to move.

Likely cause

Often it’s a stage that takes a while without much visible change: Checking the backup file reads the whole backup before a restore; Verifying reads everything again; Cancelling — finishing the current step… waits for the current step to end. For .gz images the total size is only an estimate until the end. Some drives also pause for a moment while they catch up on writing.

What to do

1. Look at the amount processed and the speed. If they’re changing, it’s working.
2. Give it several minutes before deciding it’s stuck.
3. If nothing has changed for a long time, press Cancel and confirm, and let DiskSnap finish the current step.
4. Check the log for what it was doing (see below).

Important

Unplugging a drive mid-operation is a last resort. It leaves the target incomplete, and could interrupt a write in progress on the drive itself.

The drive disappeared, or the USB was disconnected

Problem

The operation fails with The drive stopped responding or was removed or The card or drive was changed or removed during the operation.

Likely cause

The drive was unplugged, knocked, lost power or lost its connection. Loose ports, hubs and long cables make this more likely.

What to do

1. Plug the drive back in, into a port directly on the PC.
2. Treat the target as incomplete (see below) and run the operation again.
3. For Backup: nothing on the drive changed; the unfinished file was deleted. Just start again.
4. For Clone: if the source was the one removed, DiskSnap says the source could not be read, and the target is only partly written. Clone again once the source is connected.

Important

Do not disconnect drives while an operation is running. A target may already have been changed even when the operation reports a failure.

You cancelled the operation

Problem

You pressed Cancel (or closed the progress window) and confirmed.

Likely cause

You asked DiskSnap to stop.

What to do

• Backup: the drive is unchanged, and the unfinished file was deleted. If you were replacing an older backup with the same name, the older one is kept.
• Make Bootable, Restore, Clone: if DiskSnap hadn’t started preparing the target yet, nothing was written. If it had, the target is incomplete and its old contents are gone: write it again, or format it in Windows to reuse it.

Important

The image, backup file and Clone source are never affected by cancelling.

Write-protected, access denied, read/write error, or out of space

Problem

The operation fails with one of these messages.

Likely cause and what to do

Message	What to do
The drive is write-protected…	For SD cards, slide the lock switch away from “Lock”, then remove and reinsert. Some worn-out cards switch themselves to read-only permanently.
Windows denied access to the drive…	Check ADMINISTRATOR shows in the corner, close anything using the drive, and try again.
The drive reported a read/write error…	Try another port. If it happens again, the stick or card is probably faulty or worn out. Stop using it for anything important.
The drive ran out of space	Backup: free up space or choose another folder. The unfinished file is deleted.

Important

If this happened after preparation had started on a target, it’s incomplete. See After a failed or interrupted operation.

Verification failed

Problem

The progress window shows Verify: FAILED, with a message such as Verification failed: the data read back from the drive does not match…

Likely cause

What was read back isn’t what was written. The usual culprits are a faulty or worn-out drive, a counterfeit drive that claims more space than it really has, or an unreliable connection.

What to do

1. Don’t use that drive for what you just wrote.
2. Try again in a different USB port, directly on the PC.
3. If it fails again, the drive is probably faulty or counterfeit. Replace it.
4. For a failed Backup verification, no backup file is kept. Try again; if it keeps failing, the problem is with the drive you’re saving to.

Important

The source (image, backup file or Clone source) is fine. A failed verification never changes it.

Checksum mismatch after a restore

Problem

Restore fails with The data written doesn’t match the SHA-256 recorded in the backup.

Likely cause

DiskSnap’s last safeguard: what reached the drive doesn’t match the fingerprint stored in the backup when it was made. The drive (or its connection) is the likely problem, since the backup itself passed its full check before writing began.

What to do

Treat it like Verification failed: try another port, then another drive.

Important

Don’t use that drive until it has been restored again successfully.

Windows asks to format the drive

Problem

Right after Make Bootable, Restore or Clone, Windows says You need to format the disk in drive … before you can use it.

Likely cause

The drive has partitions Windows can’t read, such as Linux or Raspberry Pi ones. Windows offers to format anything it doesn’t understand.

What to do

If DiskSnap finished and verification passed: click Cancel. The drive is fine.

Important

Formatting erases that partition, and the drive will no longer do what you made it for. Only format if you want to wipe the drive and use it for something else.

Windows shows the drive strangely afterwards

Problem

File Explorer shows odd partitions, unknown drives, garbled file names, impossible dates, or a size that doesn’t match the drive.

Likely cause

• After a successful write: the drive now has the source’s layout. Explorer only shows partitions it can read, and counts in different units from DiskSnap (manual §15).
• After a failed or cancelled write: the drive may hold a mix of old and new data, for example a new partition table pointing at old contents. That produces nonsense in Explorer.

What to do

If the write succeeded and verified, this is expected. Use the size DiskSnap shows. If it failed, don’t open or repair those files: write the drive again (see below).

The drive has no drive letter

Problem

After writing, the drive doesn’t appear in File Explorer, or has no letter.

Likely cause

Windows only gives letters to partitions it can read. A Linux or Raspberry Pi drive may have none it can read, which is normal. After a clone, the copy may also have been taken offline (next entry).

What to do

1. Unplug the drive and plug it back in.
2. Check it in DiskSnap: its card shows its partitions’ drive letters (or no drive letter) and whether it’s offline.
3. A drive for a Raspberry Pi or Linux PC doesn’t need a letter in Windows to work in that device.

A cloned drive goes offline when the original is connected

Problem

After a clone, the copy has no drive letter, and DiskSnap shows it as Drive is offline in Windows.

Likely cause

A clone is exact, including the ID Windows uses to tell disks apart. When two disks with the same ID are connected, Windows takes one offline to avoid confusing them. We saw this after cloning a GPT stick onto an identical stick: Windows logged that the two disks were the same and took the copy offline, reason collision.

What to do

1. Unplug the source before using the copy. Keep the two apart when you can.
2. Unplug the copy and plug it back in on its own.

Important

Windows’ Disk Management can bring an offline disk back online, but in a clash like this Windows is expected to give the disk a new ID when it does, so the copy would no longer be byte-identical to the source. Changing a disk ID means the drive is no longer byte-identical to the original. For a copy that goes into a Raspberry Pi or another PC, you don’t need to bring it online in Windows at all.

A larger target doesn’t show its full capacity

Problem

You restored or cloned onto a bigger drive, and it now looks the size of the original.

Likely cause

Expected. The copied partitions keep their original sizes, so the extra space sits unallocated after them. It’s still there.

What to do

If you want to use the extra space, expand the last partition or add a new one with a partitioning tool (Raspberry Pi OS, for example, usually expands its own partition on first boot). DiskSnap doesn’t resize partitions.

Important

The extra space isn’t wiped, except the last 1 MiB, which DiskSnap clears while preparing the drive. Resizing partitions with another tool is outside DiskSnap.

A copy’s checksum differs later, or four bytes at the start changed

Problem

You compare a restored or cloned drive with the original later, and they’re not quite identical.

Likely cause

Windows can change a drive after DiskSnap has finished with it. We’ve seen it write a new disk signature (bytes 440–443 of the first sector) onto drives whose original signature was blank, after both a Restore and a Clone. Windows may also write small changes to partitions it has mounted.

What to do

Nothing, usually. DiskSnap’s verification ran while it still held the drive locked, so it proved the copy was exact at that point. The files on the drive aren’t affected.

Important

Exactly when Windows does this is still being investigated.

The bootable USB doesn’t appear in the boot menu

Problem

You open the PC’s boot menu, but the stick isn’t listed.

Likely cause

The stick isn’t being detected at start-up (port, hub), booting from USB is turned off in the firmware settings, or the image isn’t bootable on that kind of PC.

What to do

1. Check DiskSnap finished with Verify: passed.
2. Try a USB port directly on the PC, and restart with Restart rather than Shut down.
3. On Windows 11, try Settings → System → Recovery → Advanced startup → Restart now → Use a device.
4. Check the firmware (BIOS/UEFI) settings for a USB boot option that’s turned off. Write down anything you change.
5. Check the image suits the PC: a 64-bit PC (amd64) image for a PC, a Raspberry Pi image for a Pi.

Important

Read the BitLocker note below before changing firmware settings. The guide Boot a PC from USB has more detail.

BIOS/UEFI boot selection: which entry to pick

Problem

The stick appears twice in the boot menu, or you’re not sure how to reach the menu.

Likely cause

Many PCs can start a stick the modern UEFI way or the old “legacy” (BIOS) way, and list both.

What to do

Pick the entry marked UEFI. The boot menu key varies by maker, often F12, F11, F10, F9 or Esc; the PC’s manual or support page has the right one. DiskSnap’s Windows installer media only supports UEFI.

The USB stick won’t boot

Problem

You pick the stick, but the PC shows an error, returns to the menu, or starts Windows instead.

Likely cause

Most often Secure Boot. Otherwise: the wrong boot entry (legacy instead of UEFI), an image that doesn’t suit that PC, or an old download.

What to do

1. Pick the UEFI entry.
2. Try a USB port directly on the PC.
3. Download the latest image from the official source and write it again.
4. Try another PC. If it boots there, the stick is fine.

Important

Verification checks the written data. It does not establish boot compatibility: check the image architecture, firmware mode and publisher’s requirements.

Secure Boot blocks booting

Problem

The PC refuses the stick, sometimes with a message such as Secure Boot Violation or Invalid signature detected.

Likely cause

Secure Boot only starts software signed by keys the PC trusts. Ubuntu is signed to work with it, and most PCs start it with Secure Boot on. Some PCs are stricter, some tools aren’t signed, and old downloads can be blocked by security updates.

What to do

1. Use the latest image from the official source.
2. Try another PC.
3. Look for a gentler firmware option first, such as allowing third-party signed software.
4. Only then consider turning Secure Boot off temporarily, and turn it back on afterwards.

Important

DiskSnap never needs Secure Boot turned off. While it’s off, the PC will start software nobody has vouched for. Read Secure Boot: why won’t my USB boot? and the BitLocker note below before changing anything.

Windows asks for a BitLocker recovery key after changing firmware settings

Problem

After changing Secure Boot or other firmware settings, Windows shows a blue BitLocker recovery screen.

Likely cause

BitLocker noticed the firmware settings changed. It isn’t caused by DiskSnap or the USB stick.

What to do

1. Put the firmware settings back exactly as they were. On our laptop, that let Windows start normally again.
2. Or enter the recovery key. For a personal PC it’s usually in your Microsoft account (aka.ms/myrecoverykey); on a work or school PC, ask your IT team.

Important

Find your recovery key before changing firmware settings, not after. Without it you can be locked out of your own files.

SD card or card reader problems

Problem

A card doesn’t appear, shows as No media detected, is locked as write-protected, or fails partway.

Likely cause

The card isn’t fully inserted, a microSD adapter is loose, the adapter’s lock switch is on, the reader is unreliable, or the card is worn out.

What to do

1. Reseat the card, and the microSD adapter if you’re using one.
2. Slide the lock switch away from “Lock”.
3. Try another reader if you have one. Built-in readers can show as SD and USB readers as USB on the drive card; DiskSnap accepts both.
4. If a card keeps failing verification, replace it.