New Logic Board ... now .... files "is damaged and can't be opened"error message

Have you run Disk Utility First Aid on the volume? Even if Disk Utility reports everything as "OK", make sure to examine the "Details" to see if there are any unfixed errors.

Try booting into Safe Mode and opening your documents.

Copy a few documents into the "Shared" folder in the "/Users" folder. See if you can open the copied documents.

Create a new user account. Log out of your main user account and log into the new user. See if you can open the documents you just copied into the "Shared" folder. If they open with the new user account, then you have an issue with your main user account. Double check to see if your main user account can open the copied files in the "Shared" folder.

Where are these files stored?

Create a new document and save it. Close the app. Then double-click on the new document to see if it will open properly.

So the apps open up correctly however any associated document file generates the error? For example, MS Word may open up normally however no document files open with it. Is that correct? I am trying to completely understand your situation.

Axel F.

Are these all files as in documents or does this include the apps as well?

Axel F.