If you get a pop-up message saying
Code: Select all
FAHCore_21.exe The application was unable to start correctly (0xc000007b). Click OK to close the application.
I'd been having problems with Core 21 WU's not folding. If my client was given a core 21 work unit, Core_21 would just blow up and the above message would pop up 3-4 times. The FAHControl panel would be stuck on "waiting on Core Run".
I'd be given a core 17 or 18 WU and it would fold fine. Several WU's later I'd be given another core 21, and yep It'd blow up.
This folding rig is a Win 7 x64 box. The card in the machine is a GTX970. I had tried updating the nVidia drivers a couple of times (also trying the "clean installation" option) but to no-avail. Tried re-installing FAH. No change. Deleted the FAHCore_21.exe file so it would be re-downloaded. No change. Trying to run the FAHCore_21.exe directly would just blow up so it wasn't FAH fault. Googling the error suggested re-installing the C++ 2010 runtimes and DirectX. Re-installed the C++ runtimes + updates a few times. No change. Ran the system file checker, came back fine. No change.
Frack it.
So I gave up on Google etc. I had a few ideas of how to go about diagnosing what was going wrong. I fired up Dependency Walker and Process Monitor to see what was going wrong and where. I traced the problem to OpenCL.dll. WTF?
The machine had had a couple of ATI cards in it at one point in its life. Turns out C:\Windows\System32\OpenCL.dll was left over from an AMD driver package. Really??? I had installed this nVidia card a few months ago, and had updated the nVidia drivers at least 2-3 times. So I went and downloaded and ran the AMD Clean Uninstall Utility and ran that. Rebooted. Re-installed the nVidia drivers. I now have an nVidia OpenCL.dll and If I double-click FAHCore_21.exe it runs!
Waited a few WU's....I finally got a Core21 work unit, and, sure enough it's folding.
THE MORAL OF THE STORY IS IF YOU EVER CHANGE FROM ATI TO NVIDIA, OR VICE VERSA, RUN THE AMD CLEANUP UTILITY.
I hope this post saves someone the half day or so I wasted trying to sort this out.