When you upgrade Symantec Endpoint Protection Manager (SEPM), you see a warning about a large number of .bak or .err files, which you may choose to remove from the files before you continue the upgrade. A large number of these files may cause the upgrade to take much longer than usual.

With an excess of .bak and .err files in the Symantec Endpoint Protection Manager data\inbox folder, the progress on the the ACL updates may appear to hang at the same place (for example, 67%) for an hour or longer.

Remove the large number of .bak and .err files from the Symantec Endpoint Protection Manager data\inbox folder before you click Continue in the upgrade dialog.

You can safely delete these backup files, but if you need them to troubleshoot, you can instead move them to a non-Symantec folder.

To remove the .bak and .err files from data\inbox:

1. Navigate to the Symantec Endpoint Protection Manager data\inbox folder. By default, this folder is located as follows:
   • 64-bit systems: C:\Program Files (x86)\Symantec\Symantec Endpoint Protection Manager\data\inbox
   • 32-bit systems: C:\Program Files\Symantec\Symantec Endpoint Protection Manager\data\inbox
2. To search within the data\inbox folder, in the search box in the upper right corner of the window, enter *.err. 
3. Select all of the files that the search returns and then move them to the Recycle Bin or to the alternate non-Symantec folder location.
4. Repeat steps 2 and 3 with a search for *.bak.
5. Close the window
    

Note: In SEP 12.1.5337.5000 (RU5) and later, a warning message is shown if the count of .bak or .err files is larger than 5000, and progress is now shown while setting the Access Control Lists (ACL's).

Endpoint Protection Manager generating too many *.err files