Thomas:
I fired it up again, and was able to edit the Label field on one of the images I had imported. Hopefully, this issue has gone for good, but... I had not changed anything on the system, since my last successful bout of importing and editing metadata. I do have occasional issues with getting Win 7 to see my USB drives. I don't think that was an issue, since the Catalog files are on the PC hard drive, not on the USB 3 where I store the images. I don't save .xml files with the images. I will try a session of Auto Import again, probably tomorrow afternoon, since I have to (hopefully) take some bird pictures tomorrow morning. I should have made a video of the strange 'disappearing text'! Thank you for your help. I will post my results with the next metadata editing session.