A new client build has been uploaded to Steam. This build should hopefully solve the various issues that trouble windows players.
Gameplay has been kept the same, this is mostly a bugfix release.
Black Forest update for May 14, 2018
New Client Build - fixing windows issues
View all patches · Build 2771238 · Last edited March 15, 2019 – 18:22:08 UTC by 
Wendy
Patchnotes via 
Steam Community