Have you guys had any success in fixing your issue? I too am experiencing really slow performance. I installed ArcMap 10.5.1 on Win10 Pro on a brand new machine, no previous version on the HDD. Arc loads fairly fast, probably faster than with previous versions (my new machine is also much faster), but when I try to select a bunch of features from a .shp file the whole process grinds to a hold. So far I have tried setting the TEMP folder to c:/Temp and I reset the %APPDATA%\ESRI folder. but neither of those worked.
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