Thanks for the reply
My photos are on the same location as for PSE - I have no problems getting the photos on PSE and working with them.
I did not rename the photos or the Folders.
My photos are stored on a home network, external drive - NAS and I am not aware of any drive letter change. I figure if I am not experiencing any difficulties accessing my photos in PSE that the issue is with Lightroom.
My operating system is Windows 7 Home premium, 64 bits.
The LR catalog upgrade from PSE doesn't recognize the locations of photos stored on NAS:
Two possible workarounds:
1. In the left-hand Folders pane of LR, if the parent folder on the NAS containing all your pics' subfolders isn't showing, select one of the folders, right-click it, and do Show Parent Folder. Keep doing that until the root folder of all your pics' subfolders is showing. Then right-click that root folder and do Update Folder Location and select the correct NAS location.
2. If that doesn't work, in PSE 6, move all the photos to a local drive. Then in LR upgrade the PSE catalog. In LR, move all the photos back to the NAS. (Painful.)