It seems to me that in this folder several files ( not all) have been corrupted. Even doing the recommended procedures, the file does not open. Maybe I have to delete them.
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I discovered that I must go to Proprieties and make every move:
1_ Right-click the file or folder and select Properties.
2_ Under Group or User names, click your name to see the permissions you have.
3_ Select Edit, where you can have permissions like full control, modify, read & execute, read, write or special permissions. Choose the permissions you need and click Ok.
Than it works