The iTunes Library.itl file is locked, on a locked disk, or you do not have write permission for this file. This happens commonly because, somehow the iTunes Library.itl file got set as read only. You can fix this by doing the following steps. On your Mac, select a disk, folder, or file, then choose File  Get Info. If the information in Sharing & Permissions isn’t visible, click the disclosure triangle. Click the lock icon to unlock it. Enter an administrator name and password. However, you can transfer the Photos Library onto your Mac, where Duplicate File Finder can scan it. Troubleshooting If there are folders that have not been rescanned due to lack of access, you can edit this in the Get Info window in the Finder.

Your home folder contains many files and folders that apps on your Mac have permission to read or modify. If you use Get Info or other methods to change those permissions, you could experience issues such as these:

• Changes that you make in System Preferences aren't saved after you quit System Preferences.
• Changes that you make to the Dock aren't saved after you log out of your user account.
• Windows that were open the last time you logged out or quit an app (before you changed permissions) open again after you log in or open the app.
• You're asked for an administrator name and password when moving certain items in the home folder.
• You repeatedly get a message that macOS needs to repair your Library to run applications.
• When saving changes to an item, you get a message that the file is locked or you don't have permission to save.
• Preview, TextEdit, or other sandboxed apps unexpectedly quit when opened.
• You get an alert that the startup disk has no more space available for application memory.
• Activity Monitor shows that Safari or SafariDAVClient is using a large amount of system resources.
• Your Mac performs slowly.
• iTunes says that your device cannot be synced.
• Photos and videos that you import into Photos or iPhoto don't appear within the app, but do appear in Finder. Or your library needs to be updated or reselected each time you open Photos or iPhoto.

Reset permissions

If the issue started after changing the permissions of items in your home folder , use these steps to reset permissions.

1. Turn on or restart your Mac, then immediately press and hold Command (⌘)-R to start up from macOS Recovery.
2. You might be prompted to enter a password, such as a firmware password or the password of a user who is an administrator of this Mac. Enter the requested password to continue.
3. When you see the macOS Utilities window, choose Utilities > Terminal from the menu bar.
4. Type repairHomePermissions in the Terminal window, then press Return. The Repair Home app opens.
5. Select your user account, click Next, then enter your administrator password. Click Next unlock the volume and begin resetting permissions on your home directory.
   
6. When done, click Exit to return to the macOS Utilities window.
7. Select Reinstall macOS, then click Continue and follow the onscreen instructions to reinstall macOS.
   

Mac Locked File

If the issue persists

If resetting permissions doesn't resolve the issue:

Can't See Library Folder Mac

1. Make sure that you have a backup of your Mac, then erase your startup disk.
2. When done, reinstall macOS.
3. After installation completes and your Mac restarts to the setup assistant, create a new user account using a different name than the one you were using before. Any difference in spelling is enough.
4. If you made a Time Machine backup, use Migration Assistant to restore all your files from the backup.