VMs are indispensable for testing software. At work, I had previously used VMware Server 1.x on Windows XP without any real problems. Unlike Workstation which might actually be better for test VMs, Server is free, and it is always easier to use free than to get approval for the company to spend money. So when I recently received a new laptop as part of the standard hardware replacement cycle at work, I updated to Vista. This was after it was ordered with XP because Vista is not approved software, and exceptions are too much bother to get but it is already covered under our licensing with Microsoft. But I digress… So of course I loaded VMware on it, but being Vista I expected I might run into some problems. I was not disappointed. It went fine for the most part, probably because I do run as a local administrator and had already disabled the very annoying UAC (User Account Control). However, when starting a VM, Vista would be completely, totally, utterly unresponsive for 5 minutes or more while the hard drive activity light went solid. Sigh.
I found some information on tweaking AV exclusions or this or that VMware setting, to no avail until I found an article that had information that actually solved the problem. It turns out to be aggressive swapping, whether Vista or VMware I am not entirely clear. The trick to the whole thing – in my situation anyway – was to set the host settings such that VMware did not allow swapping out the guest but rather kept it in RAM. I have 4G so this was not a problem for me. You will find the setting under menu item Host->Settings, over on the Memory tab. Be sure to set aside the maximum you will ever want to use concurrently, and add some for VMware overhead. I used an extra 512M but you can likely get by with 256M or maybe less. Then, and this is the most important part, select the option to Fit all virtual machine memory into reserved host RAM which is not the default. That is really the core of the solution, once you have enough memory allocated. Incidentally, VMware will tell you if you didn’t give it enough memory when you try to start a VM that pushes it over the limit.
Not ideal as you do need a fair bit of RAM, but it does solve the problem.