Update: I fixed the problem. The crucial step after deleting the app and the TorBrowser-Data folder was rebooting my Mac before re-installing. After that, everything worked just fine.
I've been using Tor fine for many weeks since upgrading my Mac to High Sierra 10.13.
Today, I asked Tor to check for updates, and I was told of the 7.0.8 update. I clicked to upgrade, but upon restarting was shown the following error:
Tor unexpectedly exited. This might be due to a bug in Tor itself, another program on your system, or faulty hardware. Until you restart Tor, the Tor Browser will not be able to reach any websites. If the problem persists, please send a copy of your Tor Log to the support team.
Clicking the "Restart Tor" button brings the same dialog back.
I've uninstalled Tor and removed my ~/Library/Application Support/TorBrowser-Data folder, emptied my trash, and re-installed - but I get the same error.
I've also tried removing the app & TorBrowser-Data folder and reinstalling v6.08, v7.07, and even v7.56a6 - yet every time I start them, I get the same error.
Attempting to copy the Tor log to the clipboard always shows that there are 0 logs copied.
If removing the app and data folders isn't enough, what on earth could be causing this?
Thanks!
TorBrowser-Datafolder, I rebooted before re-installing. After that, everything worked just fine.