Prior to upgrading from 3.5.2 to 4.0.1, I had BeyondCompare configured as my Diff program. After starting 4.0.1, I went to the Diff / Merge section of the options, and the Diff section had been reset to the default values:
%VAULT_EXE_DIR%/sgdm.exe
/ro1 /ro2 /title1:"%LEFT_LABEL%" /title2:"%RIGHT_LABEL%"
Diff program settings lost during upgrade?
Moderator: SourceGear
That makes sense, because we changed the way that the diff settings were saved. They are now saved on each client machine, instead of being saved on the server and pushed to all client machines. The reason for this is to work when you're running the Vault client on a machine which doesn't have Beyond Compare installed.
I figured that out when I went to install it on a second machine. Having asked for this before because I once had beyond compare installed in different paths on my two machines, I'm glad the settings are finally per-machine. It would be really nice, though, if it could have kept the old settings during the upgrade so we all wouldn't have to reset the program. It's only a one-time thing, and I imagine that supporting that would have been a nightmare, so I'm not too concerned about it.