OK, I cleared out *every* Zoom config/cache - moving them to new directories so they wouldn't be picked up. I also moved my entire Interactive Fiction folder out of Documents to someplace else.
I launched a newly downloaded Fail Safe z5 file, causing Zoom to load, and confirmed that my settings were back to new-install.
The game is still totally broken - locking up on turn two.
I should add that the exact symptom of the lock-up is that the window loses focus. So:
1. I type command 1 as normal, it processes.
2. I can't type command 2, and it beeps. I do not see a cursor after the >, as if focus is no longer on that window. Clicking after the prompt to give me a cursor in the usual place and restore focus does not help, still can't type.
3. If I right click, or look at the Edit menu, I notice that Paste is greyed out - indicating that text input is no longer supported.
I think the fact that it still locks up after being returned to a completely virgin state confirms that either whatever has borked my Zoom is a system/environment issue outside of Zoom itself, or at least that a problem in Zoom has been triggered by something external to it.
I will raise a bug to the Zoom guy(s). This is really annoying
EDIT: Some further testing seems to suggest that it's all Z-Code games that are broken, but not including Infocom ones?? And not including Lost Pig which is zblorb rather than z5 or z8. So confusing.
Games that lock up within max 3-4 turns (usually 2):
Minster, 905, Slouching to Bedlam, Fail-Safe, Varicella (all z5), Anchorhead, Dreamhold, Make It Good (all z8)
Games that haven't locked up yet, tested each for at least 15 turns:
Lost Pig (zblorb), Trinity (Infocom z4), Hitch Hikers Guide (Infocom z5), Lock and Key (Glulx), Indigo (TADS).
EDIT 2: And now.. it's working again on those z-code games. I tried loading a save game for Make It Good, and found that worked OK, didn't lock up. So then I typed restart and found that it continued to work from the beginning of the game. Then I tried closing Zoom and running Make It Good, and then Fail Safe, from the start, and they STILL worked.
Right now I can't get any game to lock up again, where just minutes agi they would lock up every time without fail. I really can't understand how loading one save game has made some fix that persists even after closing and re-opening Zoom, but apparently it has.
This is bizarre.
EDIT 3: Played Fail Safe for 15 mins, did maybe 20 turns I guess, then just suddenly locked up again. Restarted, still locked up. Loaded Make It Good, locked up. Tried re-loading the Make It Good save that previously seemed to fix things, that locked up on the second turn after loading.