We noticed that certain file operations are very slow in Office 365 when Symantec Endpoint Protection is active.
A typical example was opening a .js file which took ~0.5 seconds where one would expect a few milliseconds at most.
We traced this down to the CreateFile API call. Process Monitor shows lots of calls by NortonSecurity.exe and ccSvcHst.exe until the call returns. And it does so every time the same file is opened.
This delay does not happen in other applications or when a folder or file extension is excluded from SONAR. It might be related to Office’s app virtualization that makes SEP scan the file more often than needed (I found some interesting research on Office app virtualization here).
Symantec, can could please see how this issue can be resolved?