Symptoms
Backup fails with:
Operating system error: A device attached to the system is not functioning
In Windows Application logs, you see this error:
Source: VSS
Event ID: 8193
Level: Error
Volume Shadow Copy Service error: Unexpected error calling routine ConvertStringSidToSid(S-1-5-21-4148555394-1870526016-119506688-1000.OLD). hr = 0x80070539, The security ID structure is invalid.
The error can mention a SID either with .OLD or with .bak.
Cause
Invalid entry inside the HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindows NTCurrentVersionProfileList registry subtree.
Solution
- Open Windows registry (in Search, type regedit and press Enter).
- Navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList
- Find the subkey specified in the error message (containing .bak or .OLD). Back up the subkey: right-click and select Export.
- Delete the faulty subkey.
- Reboot the machine.