“A javascript error occurred in the main process” is a macOS problem where the Slack app wouldn’t start and would instead give an error message. It seems that the “A javascript error occurred in the main process” issue only occurs with the 4.10 App Store version of the Slack application.

Some users who have experienced this problem and tried to come up with a workaround report that downloading Slack from its official site resolves the problem and is one way to bypass the error message and use the app normally.

Currently, it seems that the macOS version is irrelevant with regard to the “A javascript error occurred in the main process” issue. Mac users with both macOS Mojave and macOS Catalina have reported experiencing this error so, apparently, upgrading/updating your macOS wouldn’t do much to fix the Slack problem. The only consistent thing between all reported cases of this error is the version of the Slack app – version 4.10, downloaded from Apple’s App Store. The issue is not virus related.

Some users have tried reinstalling the same App Store version to no avail – the error keeps occurring. This is because simply uninstalling Slack doesn’t get rid of the user-specific data for the app, which is what seems to be at the root of the problem.

The “A javascript error occurred in the main process” issue was reported yesterday and there’s already a statement published by Slack on its official site, where the developers of the application say that they are investigating the problem and working on a permanent solution. In the meanwhile, users can try running Slack from within their web browsers or downloading the app from its official site.

Manually fixing the problem

If you are interested, there may actually be a third way to use Slack without getting the annoying error message and below we will show you how you can do that:

  1. Uninstall Slack
  2. Delete all files related to Slack from your Mac. Find and delete all Slack files that would otherwise be left behind after the app is uninstalled. Additional file leftovers may be left at these locations

Locations on Mac

  • ~/Library/
  • ~/Library/Application Support
  • ~/Library/LaunchAgents
  • ~/Library/Preferences
  • ~/Library/PreferencePanes
  • ~/Library/StartupItems

Slack File Names

  • Slack.app
  • com.tinyspeak.slackmacgap
  • com.tinyspeak.slackmacgap
  • com.tinyspeak.slackmacgap.bom
  • com.tinyspeak.slackmacgap.plist

3. Now, download Slack from the App Store and wait for it to get installed on your Mac.

4. Once you try to open the app, you will have to re-enter your login details. Inside Slack, all your previous settings should now be deleted and this should allow you to run the app normally.

Hopefully, after you finish with these steps, you would no longer be getting the irritating “A javascript error occurred in the main process” message. If, for some reason, the error keeps occurring, you can always try to run Slack from inside your browser or uninstall it again and download it from the official site rather than from the App Store.