Error ERROR: clGetDeviceIDs() -1
#1
I put back in my Radeon 6950 after removing my 980 and uninstalling nVidia drivers, I installed the new Radeon Crimson Edition software and drivers and now I'm getting the error in oclhashcat64:

Code:
Generating bitmap tables with 16 bits...

ERROR: clGetDeviceIDs() -1
#2
-1 is CL_DEVICE_NOT_FOUND so you probably didn't configure the driver properly. Have you tried regenerating xorg.conf from amdconfig?
#3
ok I rolled back my drivers from a 2016 version to 2015 and it's working now, this is for Windows 10