I've recently run into a problem with adding tags and color class to photos. Browsing a folder of images (NEF files from Nikon D3200), I've been tagging and color classing with no problem. But partway through the contact sheet, I can no longer do either. Not in Preview window or in contact sheet mode. Tried re-starting both PM and computer. Can occasionally get a few more tags done, then stops again.
Windows 7 with all updates. Current build of PM 5.