Cyberpunk 2077 is facing a number of errors and issues on PC. A lot of players are experiencing the “Expression: EXCEPTION_ILLEGAL_INSTRUCTION (0xC000001D)” error while trying to play Cyberpunk. This particular error pops up if you are playing the game on an old CPU that lacks the AVX Instructions set. In this guide, I will help players with how to fix the error 0xC000001D and Cyberpunk 2077 run on non-AVX CPUs.
Cyberpunk 2077 AVX Fix
Before we start, note that this is not a proper fix but a workaround. This fix might not work for everyone. Hopefully, CD Projekt Red will patch Cyberpunk 2077 in the future to make it work on CPUs that don’t have SVX instructions set. Here is how to fix this issue.
Open Cyberpunk2077.exe in a hexadecimal editor. After that, look for “554881ECA00000000F2970E8” and change the first byte to C3. If you don’t know how that works, just replace it with “C34881ECA00000000F2970E8” and save. Launch Cyberpunk 2077 and the Error 0xC000001D will be fixed.
If you don’t know how to do it, then check out this video showcasing how to change “554881ECA00000000F2970E8” to “C34881ECA00000000F2970E8”. Again, this might not work for everyone and the game might still crash later on.
Also, a similar fix can be performed to improve Cyberpunk 2077’s performance on AMD Ryzen CPUs.
That is all for our Cyberpunk 2077 guide on how to fix the Expression: EXCEPTION_ILLEGAL_INSTRUCTION (0xC000001D) error and make the game run on a non-AVX CPU. If you are facing other errors and issues with the game then also see our errors and fixes for Cyberpunk 2077. If you are facing errors and issues with other PC games or your PC then also see our hub for commonly occurring PC errors and their fixes.