Working with backup errors
When a backup runs, the Datto Backup Portal records any errors it encounters while reading files or creating the backup.
You can see how many errors each backup produced and download the error details from the Errors column in the Asset details panel.
An error usually means that specific files could not be backed up, not that the entire backup failed.
Because a backup can encounter a wide range of file-system and application conditions, the messages you see are not limited to a fixed list.
Most fall into one of two groups: errors that may need your attention, and informational messages that require no action.
The most common errors are related to the Windows Volume Shadow Copy Service (VSS).
Errors that may need your attention
These errors mean some data could not be captured.
They are listed roughly from most to least common.
Review the affected files and, if the error recurs, work through the suggested action.
| Error | What it means | What to do |
|---|---|---|
| File in use / sharing violation | A file was locked or held open by another process when the backup tried to read it, so it could not be captured. This is often temporary. | The error usually clears on the next backup. If a specific file fails repeatedly, close the application that is using it or schedule backups for a time when the file is not in use. |
| Access / permission denied | The backup did not have permission to read a file or folder. | Confirm that the backup has read access to the affected location and review its permissions. Some protected system locations may report this and can usually be ignored. |
| VSS snapshot failure (Windows) | The Windows Volume Shadow Copy Service (VSS) could not create the snapshot used to back up open files. VSS errors are the most common type. | Make sure the volume has enough free space for a shadow copy, confirm that the VSS service and its writers are healthy, then run the backup again. Persistent VSS failures may require a reboot or assistance from Support. See Troubleshooting VSS errors for the full VSS error code reference and resolution steps. |
| I/O / read errors | The backup could not read data from the disk, which can indicate damaged or failing storage. | Check the health of the affected disk (for example, with a disk-check or SMART tool) and resolve any underlying hardware problems. |
Informational messages (no action needed)
These messages tell you that the backup adjusted or skipped something by design. The backup is still valid and no action is required.
| Message | What it means |
|---|---|
| Unsupported reparse points ignored | Junctions, symbolic links, and WSL files are skipped because they are not supported by the backup. The actual files they point to are still backed up if they are included elsewhere in the backup. |
| Extended attributes too large | A file's extended attributes exceeded the supported size limit (larger than 64 KB, or 1 MB in some cases) and were trimmed. The file's contents are backed up normally. |
| Symlink extended attributes cleared | Extended attributes attached to a symbolic link were removed during the backup. |
| File names with invalid UTF-8 characters | A file name contained characters that are not valid UTF-8. The file is reported so you are aware of it. |
Get more help
If the error is a VSS error, see Troubleshooting VSS errors first for the full error code reference and resolution steps.
If an error keeps occurring after you have worked through the guidance above, contact Kaseya Support and include the error details downloaded from the Errors column for the affected recovery point.
See Asset details for how to download error details.
