FAHCore_21.exe error 0xc000007b The application was unable

[BertNZ]

Hi,

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.

then this post may be of some help to you...

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.

[bruce]

Thanks for the report.

That probably also explains why it is so difficult to configure a mixed system with both ATI and NV GPUs.

[JimF]

THE MORAL OF THE STORY IS IF YOU EVER CHANGE FROM ATI TO NVIDIA, OR VICE VERSA, RUN THE AMD CLEANUP UTILITY.

I will be making that very change myself in a few days. I have found that Display Driver Uninstaller (DDU) gets rid of the junk too.

[BertNZ]

I'll have to look into DDU.

What are the chances of getting a topic stickied with a few troubleshooting steps that include running tools like DDU or the AMD cleanup? Sort of a "before you post a problem about driver issues please this first".

I know that's taking a shotgun approach... but the shotgun will be aimed at a barrel with a lot of fish in it, and you're likely to catch a few with it.

I'd be happy to write something up in Google Doc form for the admins to review before posting/working on.

[bruce]

YGPM

[beylie]

Just wanted to thank the OP. I got the same message as in the title but for FAHCore_18.exe after updating to the latest Nvidia drivers yesterday. Running the AMD Cleanup Utility solved my issue too.

[ChenZheChina]

Hello,

I got the same FAHCore_21.exe error 0xc000007b today.

But I never installed any AMD / ATi display card on my computer.

Finally, I solved this issue by copying OpenCL64.dll from C:\Program Files\Nvidia Corporation to where FAHCore_21.exe is, and renamed it to OpenCL.dll.