I just purchased a new mac and migrated everything from the old to the new. LR3 was moved over to my new Mac. I'd like to now use LR6, which I just downloaded and have done nothing with yet. My catalogs are on an external hard drive. Do I need to uninstall LR3 from my new computer? How do I then set up LR6 to recognize my external and have my photos show up in LR? Links and suggestion are appreciated. Thanks!
If the old computer was also a Mac than just double click the catalog file (LRCAT file) on the external drive and Lr6 should offer to upgrade the catalog for you and the links to the photos should be ok because the Mac uses named drives instead of drive letters.