Title:  Why does my computer run slowly after installing McAfee VirusScan?

Question:
My computer seems to run very slowly when McAfee VirusScan is installed.
When I remove it, things speed up. Why?

Answer:
C&C has received many reports of performance slowdowns on Windows 98 and
Windows ME systems after upgrading to McAfee Virus Scan 4.5.1 with Service
Pack 1.

Symptoms usually involve 10-30 second delays in clicking on the Start
menu, using Windows Explorer, or opening Internet Explorer for the first
time after starting Windows. Subsequent sessions of these applications
usually do not exhibit the symptoms.

The problem seems to result from combining the 'Download Scan' component
in McAfee with having 'Client for Microsoft Networks' installed. Removing
either one fixed things in testing done by C&C.

So, if you have these symptoms, this means:

If you don't need workgroup networking, try removing Client for Microsoft
Networks and see if it fixes things for you.

If you do need workgroup networking, try disabling 'Download Scan' from
within McAfee.

If you need both, you might consider upgrading the operating system. C&C
has received no reports of this happening in Windows 2000 or Windows XP.

Also note that if you disable Download Scan, it's important to make sure
the System Scan component is enabled. C&C recommends you turn on scanning
only for "inbound" files if performance is an issue (scanning all
"outbound" files is processor intensive).