I have the same problem with P4VS and Unreal Engine 4.10. I was happy to install P4VS because when I edit a C++ code file in VS it automatically checks out the file from perforce (instead of requiring me to manually checkout the file from the P4V GUI and then edit it) (or worse if I am lazy I will edit the file without checking it out, then later have P4V consolidate it). It’s a good add-on except it makes Visual Studio completely lock up for multiple minutes as the Card and Dungeon describes.
This is more broadly an issue with Visual Studio. Visual Studio shouldn’t ever block the basic text editing functionality when it’s doing something in the background like updating intellisense or running some plugin such as P4VS. It’s also a problem with the P4VS plugin - it shouldn’t lockup Visual Studio’s text editing functionality to do automatic background perforce stuff. Finally yes I think it’s true that Unreal Engine exposes this problem with Visual Studio and Perforce, which is too bad because P4VS is a great match for UE4.
I didn’t look at the P4VS logs like Card and Dungeon, but I’m guessing I get the same error. I suppose I’ll just disable P4VS if it doesn’t stop doing it.