Experiencing a sudden loss of performance on your file server – MsMpEng.exe slow disk access
A continuation of the issues at a customers site last week where by the server performance looked to have been improved by clearing a stuck Drive Optimization see here.
So it seems that the Drive Optimization was likely stuck due to MsMpEng.exe eating all the available resources as shown by the 100% Highest Active Time, which has since, thankfully dropped to lower levels after excluding the data disk from being scanned CONSTANTLY!
The server is covered by Sophos Central so there are no real AV concerns it just seems that Windows Defender isn’t that great, come on Microsoft get your act together!
Immediately after excluding D:\Users and D:\SharedDrives on the file server the Active Time went through the floor and other services kicked in such as Windows Updates telling me I needed updates which previously had been failing.