Fix Cyberpunk 2077 AVX Problem – “Expression EXCEPTION_ILLEGAL_INSTRUCTION (0xC000001D)” Error

Cyberpunk 2077 has finally released after much delay and the game has lived up to the hype. But, the game also has a range of errors and bugs. One of them is the Cyberpunk 2077 error code 0xC000001D with the message, “Expression EXCEPTION_ILLEGAL_INSTRUCTION (0xC000001D).” The error occurs when the CPU does not support the AVX extension set. If this error has popped up for you, there are certain things you can try. Stick around and we show you how to play Cyberpunk 2077 on non-AVX computer.

Fix Cyberpunk 2077 AVX Problem – “Expression EXCEPTION_ILLEGAL_INSTRUCTION (0xC000001D)” Error

AVX stands for Advanced Vector Extensions and both AMD and Intel support the extension set. However, if you are running an older CPU, there is a chance that it does not have AVX. Without the extension, the game will not launch and crash immediately with the Cyberpunk 2077 “Expression EXCEPTION_ILLEGAL_INSTRUCTION (0xC000001D)” error. There is no permeant solution for the problem except to upgrade the CPU. However, there is a workaround that is not a universal solution but has worked for a number of users.  

If you were unable to play Assassin’s Creed Odyssey, God Eater 3, Resident Evil 7, Death Stranding, or Horizon Zero Dawn due to the same problem – the game crashing at startup without any error on launch – the possible reason is your processor does not support AVX.

There is a solution that may be able to run the game on a processor without AVX, but it’s not worth the effort since the game’s performance would be severely hindered. You will have a software perform the functions of an AVX capable CPU.

In order to attempt the fix for Cyberpunk 2077 error code 0xC000001D, you need to download the HxD Hex Editor and target the Cyberpunk2077.exe. The file is located in the install directory of the game. Look for where all your games are installed in the Steam folder.

Once the software is installed, target Cyberpunk2077.exe and change the values

Original [Hex] (55 48 81 EC A0 00 00 00 0F 29 70 E8)

Change to [Hex] (C3 48 81 EC A0 00 00 00 0F 29 70 E8)

Save the file and launch the game. Hopefully, this quick fix should be able to fix the Cyberpunk 2077 error code 0xC000001D.

The only viable solution is to upgrade the CPU as AVX is the future and more and more games will not work without it until the point when you cannot play anything new. For the issue with Cyberpunk 2077, the solution can also be provided from the developers as the developers of Horizon Zero dawn did.


  1. lol 31 December 2020
  2. Ahmed 17 December 2020
    • Harsh Clif 18 December 2020

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