When I try "delete file" I get "Unable to delete File due to system error: null"
Most documents became unable to edit offline yesterday. I found out that by deleting, and reuploading from my back up copy, they could be edited offline again. 3 or 4 of them cannot be deleted.
This change worked for new uploaded files. But I could not edit or upload new versions for the already existing ones. I had exactly the same behavior as you describe except for