Project I have been working on in pycharm for some time was closed. When I reopen it it has lost its sources root completely as well as its interpreter. File list is completely brown background as result. . In settings Project: section doesn't even appear so I can't use that to pick the source root.
What the heck causes this and how can I fix it? I have seen it happen more than once over the years I have used pycharm. I tried removing .idea directory after closing project and reopening to no avail. Other projects are all fine and this one was too when it was last opened a few days ago.
Also when I open settings and click on Python Interpreter is gives "Nothing to show" instead of a pick box to pick and interpreter or add one.