In some scenarios a file gets encrypted more than once by LAN Crypt (deactivate encryption, move an encrypted file to an ignored folder, reactivate encryption and move the file from the ignored folder to a folder with an encryption rule).
The file can be opened but it shows a SafeGuard LAN Crypt file header instead of the plain file contents.
Known to apply to the following Sophos product(s) and version(s)
SafeGuard LAN Crypt Client 3.71
Windows XP SP2/SP3 32bit
Windows Vista (Ultimate / Enterprise / Business) SP1/SP2 32bit
Windows 7 (Ultimate / Enterprise / Professional) 32bit
What To Do
To restore the proper encryption on such files, the initial encryption wizard has to be called to decrypt multiple encrypted files and encrypt them with the proper key.