To anyone following this thread, I think I was able to get to the root of the problem!
Yes, I was able to successfully resolve it on a new, dummy test account, but I was determined to play the game on my home account. So I did some tests.
I recreated my macOS home account twice (first through Migration Assistant, second through a fresh account with the same name). In both instances, the problem persisted.
But as they say, the third time’s the charm!
First, context: my home account’s folder name has dots/periods in it [to separate my initials]. And I think that’s what causes the read/write error.
The first StarCraft was created in an era when periods were forbidden characters in paths and file names, and I guess the game still hasn’t been patched to handle that.
I recreated my home folder without periods this time, and it worked!
So I guess this is something the team could look into? It’s an edge case, but I think it might be worth investigating to improve the playing experience.
[Original post below.]
Hello, Caterpepi and Jambrix!
Thank you very much for your help!
Yes, I have also mirrored the read+write permissions, using the new admin account as reference. Still, this fix didn’t work.
I appreciate that you tried to recreate the bug. I guess my options are to either play on the new admin account or to migrate my user account onto a fresh macOS install.
I have opened a ticket. Hopefully I am to resolve the issue without having to resort to either of the two solutions above.
Thanks for all your help!