Crash on startup, new install

Are you shutting down all non-essential programs before starting the game, especially anti-virus and any backup programs that may be monitoring the Documents folder?

Try verifying local files: in the Steam library, right click on the game and select Properties, switch to the Local Files tab and then click on the 'Verify Integrity of Game Files...' button. Also in the Local Files tab, click the 'Browse Local Files...' button, then exit out of the Steam client and try launching the game directly from the app file in Finder.

 If you are using the GOG version, in the Galaxy client, select the game, then the settings icon at the top right, beside the Play button and under Manage Installation, select 'Verify / Repair'. That menu is also where you can select 'Show folder' to try starting the game from the app file.

Especially if you have a relatively high desktop resolution, you can try temporarily lowering it, to limit what the game will auto-detect. If that allows the game to start, you can then exit and restore your desktop resolution.

Try doing a clean boot and then test the game. Start or restart your Mac and hold the Shift key down as soon as the progress bar comes up in the startup window, releasing it after the desktop appears. Alternately, from the login window, hold the Shift key when you click the Log In button, and release it when you see the Dock.

Try browsing to the '~/Documents/Larian Studios' folder and delete the 'Baldur's Gate 3' folder. This folder contains the saved games, profiles and configuration files. Normally it would be best to rename this folder for troubleshooting purposes, but if you don't have any saved games that isn't an issue. Next, extract the replacement folder from this download into your '..\Documents\Larian Studios' folder, and see if that will let you start the game.

The graphicSettings.lsx file is set to 1280x720 Windowed mode, Very Low quality preset and low audio quality, which you can change in the options (manually, or hit autodetect) if this gets the game to start.

If that doesn't help, please contact Support with your full system specs. You can use the 'System Report' button from the 'About This Mac' Apple menu item, or the 'System Information' app in the utilities folder), including the OS version number, Mac model name and year (indicating early/mid/late), and model identifier.

Also include a crash report with is collected in the 'Console' application, under 'User Reports'. Alternately, the crash reports may be saved in the '~/Library/Logs/DiagnosticReports' or '~/Library/Logs/CrashReporter' folders.