That's right folks. InDesign crashed. I restarted and all my sttings had disappeared. The Mac behaves like after a clean install.
Mail settings, gone.
Safari settings, gone but bizarely remembers sites from before the crash, i.e. auto fill of the URL is still functional.
Dock, empty.
All apps are still where they belong, all data is still in my user folder but the apps aren't accessing it.
Any ideas? I'm fully backed up so I could just re-install but I'm rather busy and am hoping for a less intrusive solution.