cousta: Here's what works for me on macOS:
1. make sure that any other system account is logged out
2. open a terminal and run /Users/Shared/GOG.com/Galaxy/redists/GalaxyCommunication
3. launch GOG Galaxy
GalaxyCommunication will immediately exit if any other account is still logged in. I assume it's a poorly thought-through attempt to prevent GOG account sharing.
lv2jmp: It appears that if you are logged into gog.com the website, this counts as a second connection. Once I closed the gog.com window in the browser, this workaround solved the problem for me!
I have two entries there, "GOG Galaxy.app" and "GOG Sp. z o.o.". They are enabled even if "Launch GOG Galaxy at system startup" is disabled in GOG Galaxy Settings. I don't know why or what they do, so I had them disabled. On update GOG Galaxy would complain about service failure and shut itself down. After I enabled them it worked again.
None of those solutions worked for me. I had to:
1. Uninstall GOG Galaxy using an external open-source app called PearCleaner, then install it again (GOG Galaxy started to launch). I also uninstalled Baldur's Gate 3 using PearCleaner.
2. Download and install Baldur's Gate 3 through GOG Galaxy, then close GOG Galaxy manualy or by kill command.
3. Run Baldur's Gate 3 manually by clicking on: /Applications/Baldur's\ Gate\ 3.app/Contents/MacOS/Baldur's\ Gate\ 3\ GOG
(This starts the Larian Launcher from the terminal)
4. Follow the instructions from Larian Studios to set the graphics to 1280x720 in the file: $HOME/Documents/Larian\ Studios/Baldur's\ Gate\ 3/graphicSettings.lsx
For more information, visit:
https://larian.com/support/faqs/crashing-upon-startup-mac_91 Thanks to these steps, there's no need to use the crashing GOG Galaxy, and the game works perfectly from the Larian Studio launcher:
/Applications/Baldur's\ Gate\ 3.app/Contents/MacOS/Baldur's\ Gate\ 3\ GOG
[mac M1, os Sequoia 15.0]