

Now restart your Mac and test to see if you can open the Messages app.Delete this file by dragging it to the Trash folder (you can also move it to the Desktop as a backup measure, if you want).This will open a hidden folder called Library.Press and hold the Option key and while pressing the Option key, click Go and then Library.Deleting this file may resolve your problem. Your problem can be a result of the corrupt Messages. Once your computer turns on, try again.This time restart your Mac normally (do not press the Shift key). In either case, restart your Mac to exit Safe Mode.Login (you may have to log in a few times).Keep holding the key until you see the login window.Then restart your Mac and immediately press and hold the Shift key.You may want to try to use Safe Mode to start up your Mac to fix this problem. Note: if you are running macOS High Sierra or earlier, go to the App Store to update your Mac.If there is an update available, click the Update Now button and follow the onscreen instructions. Make sure that your Mac is running the latest version of the macOS software. Then start up your Mac by pressing the power button.Wait until your computer completely turns off.Restarting your Mac may fix your problem.

