Originally Posted by
DanK
The F2 shortcut, which is the same shortcut Windows uses, is the simplest option, as Andre posted, and it works fine on a single file. You can access the same function by selecting the image in the library module and pulling down the "library" menu. One option on that menu is to rename the file.
Richard--AFAIK, you can't use Lightroom without its catalog.
To avoid losing photos, you can do all of your file management for photos already imported from within Lightroom. if you do it externally, you just have to sync or re-sync the directory.