Since last windows update, sourcetree won't load (exception 0xc0000409)

mehuge

Faulting application name: SourceTree.exe, version: 1.6.14.0, time stamp: 0x54ea9dbe
Faulting module name: d3d9.dll, version: 6.3.9600.17415, time stamp: 0x54505402
Exception code: 0xc0000409
Fault offset: 0x00000000000275be
Faulting process ID: 0x1f70
Faulting application start time: 0x01d05dbce7d1deed
Faulting application path: C:\Program Files (x86)\Atlassian\SourceTree\SourceTree.exe
Faulting module path: C:\Windows\SYSTEM32\d3d9.dll
Report ID: 26555fbf-c9b0-11e4-8269-d8cb8a18af95
Faulting package full name:
Faulting package-relative application ID:

mehuge

Well, bit of a weird one.  Looking around for problems to do with d3d9.dll saw things to do with graphics drivers and repairing directx.  Tried updating graphics drivers, same problem.  Ran dxdiag.exe which crashes trying to analyze directshow, but on re-run you can ignore directshow, and its otherwise reporting no problems.

One of my games (H1Z1) does not load, but its beta so maybe an unrelated issue, but broken DirectShow is a concern.

So still no where near closer to a solution, I searched my PC for d3d9.dll and found various versions, most of which are small (~200KB) only one of which is the same size as the one in system32 (2.1MB).

So I copied this version (same version) of d3d9.dll into the sourcetree folder, and lo and behold sourctree loads.

So, is the one in system32 corrupt I thought? 

/c/windows/system32/d3d9.dll
972b9c13c75465b0d5a527584bb5819f */c/windows/system32/d3d9.dll
/c/Program Files (x86)/Atlassian/SourceTree/d3d9.dll
972b9c13c75465b0d5a527584bb5819f */c/Program Files (x86)/Atlassian/SourceTree/d3d9.dll

an md5sum says not.

Bit strange, but at least I have a work around.