Vault Corrupting Archived files

Hi,

I have been having a serious issue with my vault file archiving system for the past several months. The archiving seems to be randomly corrupting my files, mostly excel and pdf files. I get the following message "The file you are trying to open.......is in a different format than specified by the file extension. Verify that the file is not corrupted and is from a trusted sourec before opening the file."

The only way I can get the file to open is by manually recreating the placeholders, which is a huge pain. Symantec techs have not been able to provide me with a real fix. 

Has anyone else had this issue? I am using version 10.0.2

 

Thank you