When I connect to the Asset Server, and try to Compare assets, I get a message saying I have no installed supported merge tools.
But p4merge.exe is in C:\Program Files\Perforce where I would expect it to be found. Any ideas on how to fix this?
Are you running 64-bit Windows? Unity only seems to recognize the 32-bit installation of P4Merge; try uninstalling P4Merge and installing the 32-bit version.
With Unity 5 (which has a 64-bit version), things are a bit different. The 32-bit version of P4Merge will only work if you have the 32-bit version of Unity installed.
In addition, Perforce needs to be installed on the same drive and in the same relative location as Unity. Near as I can determine, Unity is literally navigating up one directory, then looking for a folder named “Perforce”. If it can’t find it, then P4Merge won’t show up in the list.