Mar 08, 2017  'macOS needs to repair your Library to run applications. Type your password to allow this.' They just keep coming up. I've tried setting the permissions on the home and library directories, by doing a Get Info-Sharing & Permissions-Select User-Select Read & Write-Apply to Enclosed Items. Feb 26, 2018  Video showing how to fix 'macOS High Sierra needs to repair your library' error. Detailed instructions - https://www.pcrisk.com/computer-technician-blog/mac/.

1. Macos Needs To Repair Your Library To Run

Follow these steps to use the Photos library repair tool:

1. Hold down the Option and Command keys while you open Photos on your Mac.
2. In the dialog that appears, click Repair to start the repair process.

You might be asked to type in your user account password to authorize the library repair.

The repair tool analyzes the the library's database and repairs any inconsistencies it detects. Depending on the size of your library, this might take some time. When the process is completed, Photos opens the library.

Macos Needs To Repair Your Library To Run

If you repair a library that's automatically updated with iCloud Photos, the entire contents of the library re-updates with iCloud after the repair process completes.