I have three guest servers that all crashed last week. They are all missing the same folders and files. Some files appear to have reverted to older versions (e.g. vmtoolssd.exe) and files updated by Windows update. Also, I get a access denied when I try to open c:\windows\system32\drivers\ folder. We attempted to restart two of the quests and they don't boot. One is still running. This happened to two servers at almost the same time. The third server is in a separate datacenter from the other two and crashed about 14 hours after the first two. I need help determining how this happened.
Windows 2012R2 (with MS updates though August)
Dell PowerEdge R630 servers
Dell Compellent 4020 storage
ESXi 6.0.0, 3620759.