Please make sure you are opening the correct catalog. Click on file >open recent it will gonna show you the list of the recently opened catalog.
Also may i know are you using a mac or windows, also where is the catalog stored on the computer is it a internal drive or a external drive.
I am using Mac. It is stored locally:
I only have one catalogue called Weddings 2015 so it is for sure the correct one. In the past I used to have one catalogue per wedding but as I wanted to utilise the LR mob app I decided to merge all weddings under one year. I created this catalogue from scratch after I had upgrade to Lightroom CC.
I created a log report after I opened it again and all folders were "reset" - if you like I can send you that?
If you go to "Previous Import" in the library module, what do you see?
After I had the issue i had to reimport my photos (as I have clients waiting for their photos) and I can see my last previously imported set of photos that I imported. There it looks fine.
When I re-import stuff then it works fine. I even did a quick restart and it seemed to be fine. But if I wait a day or by end of today and do it then I suspect it might happen again.
Now I have to export all photos I have worked on before going to bed :/
When you have chosen Previous Import, right-click on any of the photos and choose "go to folder in the library". That will make that folder display in your library tree, and you shouldn't lose them again.
I think you are misunderstanding my issue....
I can always see my library tree after an import. As such: https://www.dropbox.com/s/hzjipi9w43881ax/Screenshot%202015-09-21%2022.13.23.png?dl=0
My problem is that after 1 day or more and I restart lightroom then my folder tree is reverted to one older state (always the same state). Even collection come back which I have removed totally.