Our Moodle Data folder was on C drive. It's getting full, so I copied it over to E drive. I edited the data path, and it seems all courses find their contents. I thought that's easy!
But I laughed too early. The problems came when our teachers try to update files which are already in the data folder. They couldn't rename, delete or upload newer version files to Moodle. It gives error messages say, "can't rename ...", "Error deleting whatever file". It's okey for loading brand new files.
There are many more folders to fix. I wonder if I have other choices? Thank you very much!!!