Another thought crossed my mind:
I have occasionally seen watchman trying to watch someone’s entire home directory. This also happened to me once and I think it was around the time I was having trouble with File System Events.
If you have several JavaScripts projects and other things in your home directory, including several node_modules
directories, and watchman is trying to watch the whole tree then it can take forever trying to scan them. At least that seemed to be happening when I found watchman watching my whole home directory. That could cause the symptoms you’re seeing. i.e. watchman not responding in time and therefore rebuilds of your project not working.
Have you tried running watchman watch-del-all
? If so, did it by any chance print out a path that is not one of your Expo projects?