A number of users have upgraded to High Sierra for added security, better photos, and other fancy features. But after upgrading, some of them claim to receive an error message – ‘Mac OS needs to repair your library to run applications error’.
This error can be annoying because it pops up each time you open any application in your Mac. To help you resolve the issue and enjoy the new High Sierra features, we provide some effective solutions in this article. Try it out and let us know what worked for you.
Solution 1: Run First Aid feature
‘First Aid’ is a powerful feature that can be used to perform disk repairs. It can also be used to fix issues when your apps don’t run properly or if you receive error messages when opening applications like in this case.
To run First Aid, follow the steps below.
- Open ‘Finder’ and select ‘Utilities’
- Click on ‘Disk Utility’ and select ‘First Aid’
- Click ‘Run’ in the First Aid dialogue that appears
Wait for ‘First Aid’ to complete the necessary repair process and ‘reboot’ your Mac to check if you are able to run the applications without any issues. If this method doesn’t fix the issue, try the next solution.
Solution 2: Repair the specific application producing the error
There is also a possibility that the specific application you are trying to open is producing an error. To resolve this problem,
- Open the application by clicking on ‘Option and Command’ keys
- In the popup window that opens, click on ‘Repair’ to repair the application
Wait until the program is repaired. Then ‘restart’ your computer and check if the issue is resolved.
Solution 3: Use the Terminal
- ‘Restart’ your Mac and press ‘Command + R’ keys to enter ‘Recovery Mode’
- Then go to ‘Utilities’ and open ‘Terminal’
- Type ‘resetpassword’ and click ‘Return’
- Choose your ‘System drive’ (which is usually Macintosh HD/SSD) and select your ‘username’
- Click on ‘Reset Home folder Permissions and ACL button’
Once this step is complete, ‘restart’ your computer and check if the error persists. If it does, you might want to ‘reinstall High Sierra’ as explained in the next step.
Solution 4: Reinstall High Sierra
It is possible that the upgrade to High Sierra was not successful in the previous attempt as a result of which you may be receiving the error. In that case, you can try reinstalling High Sierra using the steps below.
Note: Before you begin, make sure you have a backup as reinstalling OS will delete all data on your system.
- ‘Restart’ your Mac and when the startup sound appears, press ‘Command + R’ to start ‘Recovery Mode’
- In the recovery menu, select ‘Reinstall Mac OS’ and click ‘Continue’
- In the next step, choose your ‘Mac hard drive’ (which is usually Macintosh HD/SSD)
- Choose ‘Install’ and follow the on-screen instructions to complete the installation process
If these methods don’t work for you, you can downgrade to Sierra and check if it resolves the issue. But before you do so, please make sure you have a backup as reinstalling OS will delete all data on your drive. You can also refer how to reinstall Mac OS without losing data as a guide.