Windows Application Log · Event 8193
Event 8193: The shadow copy service hit an error during a backup
Volume Shadow Copy is the Windows feature that lets a backup read files that are open. Event 8193 means one of its internal calls failed. The message names a routine you have never heard of; the part that matters is the error code in brackets at the end.
Also written as VSS 8193Volume Shadow Copy Service errorUnexpected error calling routinevss error backup failed
- How oftenUncommon
- Vendor calls itError
- LogApplication
- SourceVSS
The fields that decide it
Everything else in the log line is context.
- Routine name
- The internal function that failed, such as RegOpenKeyExW or IVssAsrWriterBackup. Useful only as a hint at which part of the process failed — registry access, disk layout, or a writer.
- hr / error code
- The actual failure, in brackets at the end of the message.
-
0x80070005Access is denied. Nearly always a permissions problem on a registry key or the System Volume Information folder. -
0x80070539The security ID structure is invalid — a stale SID left in a permission list, common after a domain migration. -
0x8007000eOut of memory. Usually a very large volume with too little space for the shadow storage area. -
0x80042306The shadow copy provider could not allocate space. The volume is too full to hold a snapshot. -
0x800423f4A writer had a non-transient error. The specific writer, found via vssadmin, is the real problem. - Writer or component
- When present, the application whose data was being snapshotted. SQL Server, Exchange and Hyper-V writers fail for their own reasons and are diagnosed in those products, not in VSS.
- Volume
- Which volume was being snapshotted. A failure on one volume and success on others narrows it to that disk's free space or permissions.
Common questions
Does Event 8193 mean my backup failed?
Very often yes, and silently. Many backup products report success at the file level while the shadow copy that would have captured open files did not complete. If you see 8193 around your backup window, verify the backup actually contains a recent copy of the open files you care about rather than trusting the job status.
How do I fix VSS error 0x80070005?
Access denied during a shadow copy is normally permissions on a registry key or on System Volume Information. Run 'vssadmin list writers' as administrator: a writer in a failed state names the component. If none are failed, the usual culprits are the COM security settings for the VSS service or the NETWORK SERVICE account having lost rights to HKLM\SYSTEM\CurrentControlSet\Services\VSS.
Why does VSS fail on a full disk?
A shadow copy needs somewhere to store the original contents of blocks that change while the snapshot exists. That space lives on the volume itself by default. If the volume has no room, the snapshot cannot be created and you get errors such as 0x80042306. Freeing space, or moving the shadow storage to another volume with vssadmin, resolves it.
What are VSS writers and why do they matter?
A writer is the part of an application that knows how to quiet its own data so a snapshot is consistent — SQL Server flushing transactions, for example. If a writer fails, the snapshot may still be taken but the application's data inside it may not be usable. 'vssadmin list writers' shows each writer's state, and a writer stuck in an error state is usually fixed by restarting the owning service rather than anything in VSS.
Read next
- Read alongside Event 7031: A service terminated unexpectedly The Volume Shadow Copy service itself terminating unexpectedly, a harder version of the same failure.
- Usually comes before Event 153: A disk read or write had to be retried Disk I/O being retried. Snapshots are sensitive to slow storage and time out on it.
- Usually comes before Event 51: A paging error on a disk Paging errors on the volume being snapshotted.
- Related Event 455: An internal Windows database could not open its log file Another Application-log error whose meaning is carried entirely by a numeric code rather than the message text.
Vendor documentation
Last reviewed 6 September 2026