Constant freezing after update to 4.5.1

I've updated to 4.5.1 and I can't get Unity to work anymore..

Every other time (works the first time, freezes on 2nd or 3rd time) I press play, it freezes. Every time I make script change, it freezes. 4.3 worked fine, but downgrade isn't an option.
I am using NGUI, Photon and UnityVS (all updated to latest versions).

I am running Win7 x64 Ultimate.
Here's detailed dxdiag: https://dl.dropboxusercontent.com/u/5102757/DxDiag.txt

 

The editor log when Unity is freezing ends on this line:

Begin MonoManager ReloadAssembly

Anyone have any ideas what could be causing this?

 

I am still getting the freezes, I don't know what it is. Could it be shader compiler? Here's the shadercompiler log I am seeing:

Base path: C:/Program Files (x86)/Unity/Editor/Data
Pipe name: \\.\pipe\UnityShaderCompiler-1-8984
Cmd: getPlatforms
Unhandled exception: Readfile from pipe failed. GLE=The pipe has been ended.



Quitting shader compiler process

 

No I don't have antivirus. It doesn't crash in my other projects (without Photon but with UnityVS) but it's not an indication that it's Photon's fault yet. This one is a very complex project, I am also using my own dlls. Also I updated Photon to latest version and haven't seen any complains of crashes on their forums.

 

ok figured it out. It was Photon after all, with their recent update I needed to add connection termination logic to OnApplicationQuit() as follows:

void OnApplicationQuit()
{
_peer.StopThread();
_peer.Disconnect();
}