My old desk top computer and my laptop recognized my external hard drive as Drive J for Lightroom work. I now have a new desktop computer that I installed LrC on. The Drive Windows assigned was L. I tried changing it to J, but it did not work. On Lightroom Queen, I got directions on how to change drives through Disk Management. When it gives a list for available Drives, J is not on it. I sat on the Chatroom feature here on Adobe for 1 1/2 hours and got no where. I tried renaming my Laptop to a different Drive letter but then I could not access all my files. Any suggestions or sure fixes that are not chancy or round about? (I have seen a number of posts in various places that don't really fix the issue.)
You were on the right track, but your new computer must have multiple devices connected that already occupy 😧 E: F: G: H: I: J: K:
Do the External Drive rename again but this time choose a drive letter like P: (for Photos) or another closer to the end of the alphabet, then there is little chance that Windows will have used this Drive letter.
(You do not rename any internal drives!)
Once Windows recognizes your external as Drive P: you then open the Lightroom-C Catalog and re-link the catalog folders (that will show as [ J:? ] missing ) to the new Drive name.