AhsayCBS (DIY)AhsayACB cannot back up UsrClass.dat - file in use by another process
June 3, 2025
Product Version
AhsayOBM / AhsayACB: 7.3.0.0 - 7.17.x
Operating System
Windows XP / Windows 2003
Symptom
When performing a backup on the 'UsrClass.dat' file, the following error message is received in the backup report:
| No. | Type | Timestamp | Log |
| * | ... | ... | ... |
| * | info | ... | ... |
| * | erro | YYYY/MM/DD hh:mm:ss | [New File] File="C:\Documents and Settings\username\Local Settings\Application Data\Microsoft\Windows\UsrClass.dat" Error="[IOException] The process cannot access the file because it is being used by another process." |
| * | ... | ... | ... |
Cause
The message suggests that Windows currently lock the corresponding file during the backup operation. Even with Volume Shadow Copy enabled, the UsrClass.dat file cannot be backed up if the corresponding operating system account is logged in while the backup job is still running.
Resolution
To resolve the issue, ensure that the corresponding operating system account is logged off when the backup job is in progress.