Witcher 3, The - Wild Hunt Discussion
Trainer Tools and Resources
A "verify integrity of game cache..." sound good as a first step, mods can also be the cause
Tried the game with latest trainer, followed the steps you mentioned...no problems at all
Bring up your list of games in your Steam Library.
Right-click on your game and select Properties.
Select the Local Files tab the top.
Select Verify Integrity of Game Cache and let that run.
It will tell you at the end the results and repair it.
Where did you buy the game? They might have a similar file checking feature at that site. If you bought it from GOG, you can have GOG Galaxy check the installation.
If not, you might need to uninstall and reinstall the game since you're having trouble with it even without the trainer running.
If you didn't find Witcher 3 on your Steam library, you bought it somewhere else, and that means usually you'll have to re-install the game
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