Hello RoseTheCorgi,
Thanks for posting in the Apple Support Communities. We're happy to look into this with you. Thanks for letting us know what actions you've already performed. This will help us avoid asking you to repeat any actions.
Have you tried starting up your MacBook in safe mode and then accessing the Files app? If not, this is a good step to try as it will disable certain startup items and extensions, as well as perform checks of your system, much like First Aid in Disk Utility. You can read full details about safe mode here: How to use safe mode on your Mac - Apple Support
To get you started on the process, we've listed the actions you'll need to take below.
How to use safe mode
Determine whether you're using a Mac with Apple silicon, then follow the appropriate steps:
Apple silicon
1. Shut down your Mac.
2. Turn on your Mac and continue to press and hold the power button until you see the startup options window.
3. Select your startup disk, then press and hold the Shift key while clicking “Continue in Safe Mode.”
4. Log in to your Mac. You might be asked to log in again.
Intel processor
1. Turn on or restart your Mac, then immediately press and hold the Shift key as your Mac starts up.2.
2. Release the key when you see the login window, then log in to your Mac.
3. You might be asked to log in again. On either the first or second login window, you should see ”Safe Boot” in the upper-right corner of the window.
Once you've tested in safe mode, be sure to reboot your Mac and see if the issue continues. Please let us know the results as this will help us research next steps for you to try.
Best regards.
