I shut down the computer with a project open and the .iws file got corrupt ( I don't remember what exactly was the error message; there were two of them, and one told something about code style scheme and the other one told something about the .iws file ), causing IDEA to fail opening project. However, when I erased the .iws file, IDEA started up normally. So, I guess that when an error is encountered reading the .iws file, IDEA should retry loading the project as if the file were missing.