I installed Acceleration and the new SDK but flight sim wouldn't start. It just gave up before showing anything. Panic set in.I finally found the problem and I post here in case anyone else falls for the same trap.Looking at the DLL.XML file I found that the Acceleration install had placed an addon with the wrong path thus: Microsoft Flight Simulator SDKSDKMission Creation Kitobject_placement.dllHowever, I had installed the SDK in the following path: SDKSDK.As soon as I changed the path to: ..SDKSDKMission Creation Kitobject_placement.dll FSX then started normally and my panic subsided. Why on earth one addon was given a different path by the Accleration install I will never know. But when FSX just refuses to get to first base after a patch, diagnosis is not an exact science thanks to the lack of error messages.I think it is fair to comment that this problem is down to Microsoft.

Question: Had you at any time in the past installed the SDK to the default location?The Acceleration installer reads the Registry entry to find the full path to any previous SDK, so if the Registry is incorrect... :)

No Bill. I installed in my current location from the initial FSX install and had updated the the original SDK when the first update came out without problem. FSX & SDK has only been installed on my machine once. Other addons have been added to the DLL.XML file without problem.