The backup finishes, the progress bar reaches the end — and some photos or videos didn't make it. Maybe a handful, maybe a few hundred. Often it's the long videos, or the oldest photos, which is exactly the content people care about most.
It almost always comes down to one of a few causes, and each has a simple fix. This guide goes through them, and explains what each of VaultDrive's failure messages means.
1. The original is only in iCloud
Symptom: on iPhone, older photos fail or are skipped, while recent ones copy fine.
Cause: with Optimize iPhone Storage on, the phone keeps smaller versions of photos you rarely open, and the full-resolution originals live only in iCloud. A real backup needs the original, so it has to be downloaded first — and that needs a connection.
Fix: connect to Wi-Fi and back up again. Leave it time; a large library can take a while to download. How to back up iCloud Photos to a USB drive covers this in detail.
2. A video is bigger than the drive's format allows
Symptom: photos copy fine, but long videos fail.
Cause: the drive is formatted FAT32, which can't store any single file larger than 4 GB. A minute of 4K video at 60 fps is roughly 400 MB, so a clip of about ten minutes exceeds it — and ProRes can pass 4 GB in under a minute.
Fix: copy anything you need off the drive, reformat it as exFAT, and run the backup again. exFAT vs FAT32 for phone backups explains how.
3. The drive ran out of space
Symptom: everything copies until a point, then nothing more does.
Cause: the library is bigger than the free space on the drive. It's easy to underestimate, especially if Optimize iPhone Storage is on — your library's originals take up much more space than the phone's Photos figure suggests.
Fix: free up space on the drive or use a bigger one. A drive at least twice the size of your library leaves room to grow.
4. The drive can't be written to
Symptom: nothing copies at all, even though the drive appears.
Cause: the drive is formatted NTFS, which phones can usually read but not write, or the drive is physically write-protected — some SD cards and adapters have a small lock switch on the side.
Fix: slide the lock switch off if there is one, or reformat the drive as exFAT after copying anything you need off it.
5. The photo couldn't be read from the phone
Symptom: a few individual items fail, with no obvious pattern.
Cause: the photo was deleted or changed while the backup was running, or the file on the phone itself is damaged.
Fix: retry the failed items. If one keeps failing, open it on the phone — if it won't open there either, the original is damaged.
6. The copy didn't match the original
Symptom: a file was copied, but marked as failed.
Cause: after copying, the file on the drive didn't match the original — usually because the connection dropped mid-write or the drive is unreliable.
Fix: check the cable and drive, then retry. If it keeps happening with one drive, the drive may be failing.
Photos missing without any error
If photos are simply missing — no error, just not there — the app probably can't see them.
When you grant an app access to your photo library, both iPhone and recent Android versions let you choose all photos or selected photos only. With selected photos, a backup app can only back up the ones you picked.
- On iPhone: go to Settings → Privacy & Security → Photos, choose the app, and select Full Access.
- On Android: open the app's permissions in Settings and allow access to all photos and videos.
What VaultDrive's messages mean
VaultDrive doesn't just tell you how many items failed — it tells you why, grouped by reason, so you know what to fix.
| Message | What it means | What to do |
|---|---|---|
| In iCloud — not on this phone | The original is only in iCloud and couldn't be downloaded | Connect to the internet and back up again |
| Waiting for Wi-Fi — in iCloud | The original is in iCloud, and downloads are set to Wi-Fi only | Connect to Wi-Fi, or allow cellular downloads |
| Drive ran out of space | The drive is full; the backup stops | Free up space or use a bigger drive, then resume |
| Couldn't read from photo library / Couldn't read the source file | The item couldn't be read on the phone | Retry; check it opens on the phone |
| Copy verification failed | The copy on the drive didn't match the original | Check cable and drive, then retry |
| Couldn't export the file | The phone couldn't hand over the file | Retry; restart the phone if it persists |
| Over the free plan limit | The free version's 200 files or 2 GB per run was reached | Upgrade to Pro for unlimited backups, or back up a smaller selection, such as specific albums |
| Not tried — the backup stopped first (Android) | The backup ended before reaching this item | Resume the backup |
Two things you might also see aren't failures at all: already on the drive, which means an exact copy is already there, and deleted from device, which means the item was backed up earlier and has since been removed from the phone.
The iCloud messages appear only on iPhone.
How VaultDrive helps you fix failures
- It keeps going. One failed item never stops the whole backup — it's logged, and the backup moves on.
- It tells you why. The summary groups failures by reason, as in the table above.
- Retry Failed re-attempts just the items that failed, without repeating the whole backup.
- It checks before it starts. VaultDrive warns you about FAT32 drives, NTFS and read-only drives (on Android), and won't start a backup that wouldn't fit in the drive's free space.
- It checks every copy against the original's size, with an optional SHA-256 hash check, so a bad copy is caught, not counted.
- It never settles for previews. On iPhone, if an original is only in iCloud, VaultDrive downloads it — one at a time, over Wi-Fi by default — rather than copying the smaller version on the phone.
It's free for up to 200 files or 2 GB per backup, and Pro is a one-time purchase.
If a backup stopped partway rather than finishing with some failures, see phone-to-USB backup stopped halfway?
Frequently Asked Questions
Why do some photos fail to copy to a USB drive?
The usual causes are originals that are only in iCloud and haven't been downloaded, videos larger than 4 GB on a FAT32 drive, the drive running out of space, a drive the phone can't write to, and photos the app isn't allowed to see. Each has a simple fix, from connecting to Wi-Fi to reformatting the drive as exFAT.
Why won't my videos copy to a USB drive when photos do?
Almost always because the drive is formatted FAT32, which cannot store any single file larger than 4 GB. Photos are far below that, but long 4K videos and ProRes clips exceed it. Copy anything you need off the drive, reformat it as exFAT, and the videos will copy.
What does 'In iCloud — not on this phone' mean?
It means the photo's full-resolution original is stored only in iCloud, usually because Optimize iPhone Storage is on, and it couldn't be downloaded during the backup, for example because the phone was offline. VaultDrive reports it instead of copying the smaller version on the phone, and it is included again on a later backup with a connection.
Why are some photos missing from my backup without any error?
Often because the app only has limited access to your photo library, so it can only see the photos you selected when you granted permission. On iPhone, give the app Full Access in Settings under Privacy & Security, then Photos. On recent Android versions, the same choice between all and selected photos appears in the app's permissions.
What does 'copy verification failed' mean?
It means the file on the drive didn't match the original after copying, for example because its size was different. VaultDrive treats it as failed rather than backed up. It is usually caused by a connection problem or an unreliable drive. Check the cable and drive, then use Retry Failed to copy just those files again.
Can I retry only the photos that failed?
In VaultDrive, yes. When a backup finishes with failures, the summary groups them by reason and offers Retry Failed, which re-attempts just those files without repeating the whole backup. With a manual copy, you have to find the failed files yourself and copy them again.
The short version
When some photos fail to copy, it's usually originals stuck in iCloud, videos over 4 GB on a FAT32 drive, a full drive, a drive the phone can't write to, or the app not being allowed to see every photo.
VaultDrive tells you which, item by item, keeps going past failures, and lets you Retry Failed without starting over.