Special K Helper
Download Special K from Discord server: https://discord.gg/specialk
If you have never installed Special K, make sure to first install Special K using an executable from the #installers channel so Special K files gets configured correctly.
Instructions to install Reshade for Special K: https://wiki.special-k.info/en/SpecialK/ReShade
If you install a Reshade version higher than v5.0, you won't get the window with "[Click here to select a game and manage its ReShade installation]." message. In that case, you should install normally to the directory indicated by the tutorial, then rename the Reshade installer to zip extension and extract its contents.
Special K is not compatible with all games and can introduce issues that can range from in-game issues to the game crashing or not booting at all. To fix this, you can exclude the game from using Special K by using the extension functionality
You can also temporarily disable starting Special K with games to test if it is the culprit of the issues by setting the extension button on the sidebar to disabled and trying to launch the game again
A critical file is missing from your Playnite install. This can be fixed by doing an install as explained in the "Install Special K" section