It's long been a rule of thumb that the TM1 data directory should be excluded from virus scans. The results if a virus scanner has a lock on a file that TM1 is trying to write to can be... unfortunate.
Yesterday IBM published a more expansive technote on this point which can be found here.
In a nutshell the folders that they recommend excluding are:
I'm not sure that a lot of IT departments would be crazy about excluding all of these, and I suspect that the exclusion of the databases scan is more an issue of performance than stability.- The TM1 data directory
- The TM1 logging directory (if not in the data directory)
- The directory where the tm1s.cfg file is located (if not in the data directory)
- The directory where any Excel sheets (or other docs) are located and uploaded to the TM1 server as a reference
- The directory where any flat files may be written to (output from a TI process, for example) or pulled from (import into a TI process, for example)
- Any other databases being used by a TM1 process (Oracle, SQL Server, MSAS, etc.)
- The TM1Web/TM1WebEx files - by default located at: C:\Inetpub\wwwroot\