Recently, I had an issue with AutoCAD performance. Whenever I would pick an entity there was a 3-5 second delay before I could do anything with it. The issue occurred in both 2011 and 2012 versions. Usually, when I come across problems like this, I use Process Monitor. This is a fabulous tool that allows you to view everything that is going on with your computer – it monitors all of the processes:The tool can be a bit overwhelming because, well, you have a lot of things going on with your computer. If you just want to view what’s going on with AutoCAD, you can filter for the acad.exe process:So now with this filter on, I started searching for the delay when picking entities in AutoCAD. This is primarily what I was seeing in the process monitor during the delay:
AutoCAD was hanging up while accessing the file mfcm90u.dll. What is this WinSxS folder? It’s a critical folder for storage of the operating system components. Now I have a lead. Where do I go from here?
Since the problem was happening in different flavors and versions of AutoCAD, and because the mfcm90u.dll file is independent of AutoCAD, I turned my attention away from AutoCAD and towards Windows. I asked my colleagues if they have any ideas. One recommended reinstalling the Microsoft Visual C++ Redistributable Package. I did that – no luck. I installed Windows 7 Service Pack 1. Again, no luck.
I disabled McAfee Virus and Spyware Protection. Luck! The delay went away. Good, we’re getting closer. Disabling AV is obviously not a permanent solution. Perhaps I can exclude the c:\windows\winsxs folder from the on-access scans. I’ll try that and report back.