A few thoughts
1 any other antivirus installed?
2. try running the MVT program and see if it fixes anything. note session number it produces for if you call support.
3. call support. they will probably suggest a reinstall as 1st idea.
My install stable and except fot a longer scan time than I would like is working fine.
1. I have Malware installed in addition to McAfee Total Protection.
2. Tried running MVT three times and kept getting HTTP Error 503 the service is unavailable.
3. Guess support is the only thing left.
I did try a reinstall, and the slowness is still there.
Thanks for your input.
"Malware" - Malwarebytes?
If it's the always-on version there may be some conflict with McAfee.
If it is, try disabling it as an experiment and see what happens to performance.