I don't want to upgrade to CC LR6. I re-downloaded LR 5.7.1 last night, and now I can't get to hundreds of my photos. Further, my develop module has been disabled. How do I get access to all of my catalogs, and NOT use CC?
Please go to the location where the Lightroom catalog is saved and try the most recent Catalog.
Also in Lightroom , go to File > Open Recent and see if you have any other Catalog there.
And for Develop module disabled please check : Develop module disabled
Let me know if it helps.