I am getting this error now on backups, where I did not used to have this problem. My Toshiba Portege is several months old Backups were running fine. However, recently, I have installed and uninstalled various utilties, and can no longer backup.
The error code is 0x81000038.
Microsoft has a KB article for this "0x81000038" error message when you back up files in Windows 7
So begins, the trip down the rabbit hole.
Know first, that this is an upgraded system, now running Windows 7 Pro. All the upates are applied, There are no viruses, as MSE watches over the system constantly.
The KB article says:
This problem occurs because the following registry key value is missing:
HKEY_USERS\<User ID>\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders\AppData
So, I go to the registry and find that there are no user IDs that match anything I expect to see (like my windows login). (See the attachment.)
So, I decide to add the key(s) listed in the KB article. But I cnanot edit that part of the registry, permission denied. Nor can I add myself to the permisisoons list for the KEY_USERS key.