I know this is a generic error with multiple resolutions. I've tried each of those resolutions without any success. I am posting with the thought that someone may have come across another resolution.
I have one user in our organization that is receiving this error: Task 'Microsoft Exchange' reported error (0x80004005) : 'The operation failed'. Now I've been searching the forums and Google for any and all resolutions to this yet nothing seems to work.
What I have done is ...
Add Background Intelligent Transfer Service (This worked for the other user that had this error but the other has this running already)
Recreated the Outlook Profile
Removed all .oab files and attempted to download
Disabled Cache Exchange Mode
Updated Offline Address List
Recreated OAB
Verified Permissions for OAB folders
Check the timestamp for OAB
It is now just this one user that can not update their AB only to receive this error.