I store my photos on 2 external hardrives. Harddrive(a) pics 2009-2013, and harddrive(b) pics 2014-2016. LR has somehow switched the content of these harddrives in the 'folders' menu (left side panel), so that it looks like (a) has (b)'s content on it and vice versa. The content has not actually moved and is exactly where it always was (If I go to the hardrives via pathfinder the right folders are in the right place.) but apparently LR thinks it has, as a result I cant access any of my images.
What went wrong and how do I fix it?
First, Lightroom didn't do this, most likely your operating system did this.
On Windows, you should change the drive letters back to their previous letters.
OMG it worked, you're a genius and I think I love you (my husband might find this a little awkward, but I'll try to explain it to him the best I can).
Thank you so much <3