I just set up Lightroom Mobile in Lightroom. In preferences it asked for the folder for Lightroom mobile. I set up a new folder on my hard drive for Lightroom mobile inside the folder where I had stored all my Lightroom folders with pictures. Now in Lightroom I only see the Lightroom Mobile folder all of my other folders no longer show up in Lightroom. I have over 30 folders with over 8K pictures that I set up in Lightroom. What happened and how do I fix it?.
Try doing a right click (Control click for Mac) on the folder you can see. Then choose Show Parent Folder.
This is a guess. I'm hoping the Mobile folder is nested inside of the folders that have disappeared.