Perforce right-click integration in Unity stops working, "Check Out" grayed out

Occasionally, Perforce will stop working - it says it's connected, and we can see Outgoing and Incoming files, but the Version Control->Check Out choice is grayed out on all files. Any idea how to fix this? We had the same problem at my last job, we never found a solution.

Currently this is in Unity 4.6.2

 

More info: this seems to happen quite frequently, one moment someone will be able to check out files, the next they can't check out any more files. Reconnecting to Perforce doesn't fix the problem, the only thing that seems to fix it is closing Unity and reopening it.

Edit:
I submitted this as a bug, Case 668448

 

This still happens in Unity 5. Very annoying.

 

Any news on this?
We have the same problem in my team.
Not only that, but Perforce is failing to apply changes on scripts, materials, etc... (even after following CheckOut > DoStuff > SubmitChanges) and even corrupting some scenes.

 

This has gotten beyond annoying, Unity appears to lose the integration connection every 5 minutes. The only solutions I've found are:
* Restart Unity every 5 minutes
* Ignore integration and just manually check in/out everything through P4V

 

I'm getting this as well. Reported as bug 702312.

 

I've had this problem with script files. I find checking out the folder(s) they're in works well enough. Still a bit of a hassle though.

 

Ah, interesting. I work almost exclusively with script files, so that might explain why I see it so much. Will give the whole-folder approach a go, though that has the different problem of possibly preventing other people from getting access to scripts they need to work on.

The real fix, of course, would be Unity fixing the bug itself.

 

I seem to no longer have the bug after upgrading to 5.1.

 

I'm jealous; it's hit me multiple times today, and I'm on 5.1