How to fix
“macOS needs to repair your Library to run applications” error on High Sierra
on Windows

Since I’ve upgraded to High Sierra, I frequently receive an error message telling “macOS needs to repair your library to run applications.” I am not sure what causes it and how to fix it.

Many Mac users reported about annoying “macOS needs to repair your library to run applications” error that shows up on the screen several times per day when they use a computer. The problem occurred soon after upgrading to macOS High Sierra.[ref en-1]

There’s no doubt that using the latest version of the operating system is important for the computer’s security and best experience.[ref en-2] However, such error is annoying. The pop-up might show up when users try to launch a specific application or out of nowhere:

macOS needs to repair your Library to run applications.
Touch ID or enter your password to allow this.

It’s unknown what exactly triggers the error. However, you can still fix “macOS needs to repair your library to run applications” error yourself. Below you can find the most common methods to get rid of this problem.

Methods to fix “macOS needs to repair your library to run applications” after High Sierra upgrade

There are a cpuple of methods that can help to get rid of the error. Try from the easiest ones and finish with downgrading macOS or reinstalling High Sierra.

Method 1. Run First Aid

1. Navigate to Utilities.
2. Open Disk Utility tool.
3. Click on First Aid tab.
   

   

4. Select Run on the appeared pop-up.

Method 2. Use Terminal to fix the error

If the previous method did not help to fix “macOS needs to repair your library to run applications” error, try to solve the problem by following these steps:

1. Restart your Mac and hold Command + R to enter into Recovery Mode.
2. When your computer is turned on, go to Utilities and open Terminal.
3. In Terminal type resetpassword and click return.
   

   

4. Choose your Systemdrive.
5. Select your username from the list.
6. Click Reset Home folder Permissions and ACL’s button.
7. Reboot the computer and log in to your account.

Method 3. Repair the program that delivers an error

If you receive a "macOS needs to repair your library to run applications” error when trying to open specific programs, there might be something wrong with it. Thus, you should try to repair the program:

1. Hold down Option and Command keys when opening the app.
2. Click Repair button in the appeared pop-up window.
3. Wait until the issues are solved.
   

   

Method 4. Reinstall macOS High Sierra

There might be some problems with upgrading to macOS High Sierra, so you might consider reinstalling[ref en-3] it to fix “macOS needs to repair your library to run applications” error.

1. Reboot your Mac and hold Command + R to boot into Recovery Mode.
2. Choose Reinstall macOS from the appeared macOS Utility window.
   

   

3. Choose your hard drive (e.g., MacintoshHD).
4. Click Install option and follow the instructions on the screen.

Method 5. Downgrade to macOS Sierra

You can also downgrade to the older version of the operating system if you use Time Machine[ref en-4] or other backup tools. Before you proceed, create backups of your files because they will be lost. Once you have backups, follow these steps:

1. Reboot to Recovery Mode by restarting your Mac and holding down Command + R keys.
2. Choose Restore From The Machine Backup option from the appeared menu.
   
   

   

3. Click Continue and follow the instructions on the screen. You will be asked to choose your Restore Source and available backup dates.