Performance problems with virus scan

[Carl L]

We have written a C# add-in for Excel. It uses .Net 1.1 to communicate with a
server using web services. When McAfee virus scanning is enable on the client
machine the performance of the web services degrades drastically.

When the machine is not responsive the Excel process is taking up all
available CPU. Using process explorer we have found that the core .Net thread
is taking the time mscorwks.dll!ReleaseFusionInterfaces.

The virus scan is configured to only scan file that are being modified. Does
..Net write any temporary files when processing web service requests?

Has anyone else experienced this?