Update 1.8.6: Windows/Linux Users Probably Need to Rename their Config folder
just a quick message: I have been informed that on Windows and Linux, apparently the Zettlr 1.8.6 update changes its policy to require capital letter configuration folders. I have always intended for this to happen, but never managed to get it to work, so some change I did in the past month apparently finally did the trick. However, since macOS is a case-insensitive file system (both Zettlr and zettlr are the same for macOS), I did not notice this inconvenience and hence did not alert you to this prior.
But the mitigation is very easy: Simply rename your data folder from "zettlr" to "Zettlr" if you are affected.
You can find the path where this folder is located in our installation guide: https://docs.zettlr.com/en/install/