Roblox won't launch for some user accounts on mac

I can’t get Roblox to launch under one user account on a mac.

Steps:

1. visit www.roblox.com in Safari and login.
2. navigate to a roblox hosted game such as meep city
3. Click the play button
4. If Roblox is not already installed, get prompt to download installer
5. Mount installer disk image
6. Run installer
7. Upon downloading the installer, the download prompt becomes a “Play” prompt with four instruction steps. Click Play.

Expected result:

9. Roblox launches and you play the game.

Actual result:

9. Safari loses focus as if an app were launching, but the application never launches.

Google turns up some info, like Mac: Troubleshooting at roblox.com and Can’t launch Roblox on Mac at devforum.roblox.com. They suggest uninstalling and reinstalling the app.

I have done this, deleting Roblox.app and RobloxStudio.app from ~/Applications, and also com.roblox.Roblox.plist and com.roblox.RobloxPlayer.plist from ~/Library/Preferences/. Still the game won’t launch.

Note that launching the game from the Dock or from Finder, as suggested under “Other Things to Try” in the Mac:Troubleshooting page linked above, still did not cause the game to launch. Launching the game manually in this manner does all you to see in Console.app a long list of launching messages, ending in this error:

timestamp    Roblox     Command Line: Handling command line options
timestamp    Roblox     Command Line: No command line arguments
timestamp    Roblox     ERROR: Embedded application launched without command line options

Launching from the webpage in Safari also populates the console log with a bunch of entries that I believe are correlated with the launch attempt, but instead with process name com.apple.WebKit.WebContent or com.apple.WebKit.Networking.

Launching from Firefox instead of Safari did not help. Other user accounts on the same machine will launch the game just fine. But even deleting the user account and recreating it did not suffice to cause the game to launch properly.

It’s a MacBook Air (2018), running macos 10.14.4. Roblox won’t launch so it’s hard to confirm the version number, but Get Info says it’s 1.2.0.302070. It’s a non-admin account, so the installer is installing the app to /Users/username/Applications/Roblox.app instead of /Applications/. It seems to launch fine from that location for other users.

Any further help would be appreciated.