Originally posted at https://psteamcommunity.yuanyoumao.com/app/20920/discussions/0/142261352649085131/?tscn=1671305622#c5551280551719046341


I'm posting this because no one else has written up detailed instructions on how to fix this problem with The Witcher 2, nor has anyone else (in The Witcher 2 [TW2] Steam Guides) put together a Processor Affinity guide.

This guide does apply to other applications/games that suffer from this same problem, but the Processor Affinity requirements can vary from application to application. This is not generalized guidance, but instead guidance on what worked for me alone.

The motivation behind doing this discovery is as follows

• I purchased The Witcher 2 (back when I was on Windows 7
  
• I replaced that original computer with a Windows 10 machine and did not play TW2
  
• I replaced that Win10 machine with a new machine recently (Win11) and decided that I wanted to revisit the nostalgia of the TW2 before I dive in to the NextGen TW3 update that was just released.
  
• I discovered that TW2 would hang and looked for a solution. I came across a Steam Discussion thread that offered several solutions but the only thing that worked for me was setting the Processor Affinity. Since there was not a good write up of (a) how to do that and (b) a permanent solution that did not require setting affinity on each launch, I set myself the task of researching how that was done and documenting it for posterity.

When I realized that there was no Guide for this, I decided a guide would be beneficial as an alternate search location for the same information.

This may not solve all technical problems, but the manual workaround is a quick and easy way of discovering if this could solve your problems without having to do more invasive things like playing with the registry or re-installing redistributables or trying 3rd party applications of questionable safety.

This workaround and solution uses no registry hacks and nothing but the software already on your Windows 7-11 PC. (Also, for completeness, I'm pretty sure that START has been around since the 90s and Windows 95 at least, if not before. CMD has existed since 1987. But if you want to know more about the history of computing, Steam Guide's is perhaps the very worst place to try to get that info, so I'm gonna stop there.)

The CPU Affinities solution worked for me (on Windows 11)

Before applying affinities:

1. Launch game from Steam (not running as admin)
2. Launcher UI opens (after first run install activities complete and graphics settings are set)
3. Launch The Witcher 2 (TW2)
4. Wolf's head logo appears in center of the screen

Expected:

5. Game loads menu screen, haunting music begins playing, ability to launch the game

Actual

5. Wolf's head logo never disappears, must force-stop the game via TaskManager and/or Steam

Workaround:

At 2 (when the Launcher UI opens)

2a. Right-click on taskbar, select Task Manager
2b. Find TW Launcher, right click, select Go to Details (Launcher.exe)
2c. Right-click on the launcher.exe entry, select Set Affinity
2d. Unselect All Processors
2e. Select Processors 0-3, Select OK

Continue with 3 above to achieve expected results.

This has to be done each time you launch the game because Processor Affinity is not saved. A more permanent solution is available, however. The walkthrough on how to configure this for yourself is contained in a Microsoft Answers article.

How to set CPU affinity on launch via Shortcut: https://answers.microsoft.com/en-us/windows/forum/all/how-to-permanently-set-priority-affinity-with/e7fe5a46-37c8-4277-9d27-60b537c4780a

For me it would be


%comspec% is the variable for your CMD.exe path & file
/C is an argument that tells CMD to execute the command in the shortcut and then exit the CMD window. If you omit this the game will still launch but the CMD window will have to be manually closed (X or type exit and press enter)
START is another Windows execute command that allows you to start a specific program with specific settings.
/Normal tells Start to launch your program at Normal CPU Priority. You can change this, YMMV.
/Affinity is which CPU affinity should be set at launch. This is the money argument in the START command. Affinity is bit-based (binary) for each CPU but is set using HEX. If you don't understand what this means, just know that CPUs 0-3 are set with an argument

You will have to be able to self-discover the location of your Witcher 2 installation path and the location of the launcher.exe. I've installed my games on a custom D drive location so my path information isn't going to be "standard" for anyone else.

Good luck