I've a number of Server 2008 and 2003 virtual machines running on vSphere 4.
When using Windows Explorer on any of them, it runs very slow, e.g. 60 seconds + to change a folder. These folders are also shared, and browsing them from the clients over the network is perfectly fine.
It's doesn't matter if I use vSphere Client to access the VM's, or MSTSC, Windows Explorer runs very slow.
Suggestions?
It appears to be Kaspersky. I'd tried disabling it, but apparently not enough. After some more Google-fu, removing it entirely fixed it, and then reinstalling it seems to remain okay.