Application Data excluded

When I create a full backup all files and folders are backud up, except “Documents and Settings/User/Application Data”
When the backup is running I see that the folder 'Application Data" is filled, but then the program is inactive for a whil and all of the contents of the folder is being deleted. After that the program is competing the rest of the backup.
Is there an explanation?

Hi

Please enable logging to file in backup step 3, then run the backup again.
Post the log here for analysis.

Thanks