During a recent site visit I came across an NT 4 and Windows 2000 machine and these where both already virtual. Neither machine has VMware Tools installed but as it was going to be a cold migration this was not an issue.
The process meant that during the migration the disk would be converted to thin which did not seem to be an issue for the Windows 2000 machine but the NT machine would fail at 98% (virtual machine configuration) each time. I decided to try the NT machine and not touch the disk configuration and everything completed.
The next job is installing VMware Tools and this turned out to be an issue. The automated process locked on each machine to the point of having to revert back to a snapshot (taken of each virtual machine before anything is carried out). The interactive was then tried which showed that the process and machine locked when the VMXnet drivers where installed. It had been so long since an NT and 2000 machine had been seen that the need to do a custom install had been filled. Reverted both machines and carried out a custom installation making sure that the VMXnet driver was not selected and everything worked.
I hope this helps someone that comes across the same issue and has forgotten the issues of NT and 2000 within a virtual estate these days.