Wow! For some reason things are really bad now.
I created a new slider, called RENO - Exterior and went to add my slides. Although I could add single slides, when I tried to add multiple slides in a row, as soon as I held down the [shift] key I was looking at the Renovation pages and the Meta Slider menu was in red. When I clicked back on the slider menu none of the pictures were there. It didn't happen every time, but enough to be annoying.
As you suggested I saved the Slider then reloaded the page, then started moving the slides into order. No sooner did I have them in order and saved the slider then they were all back in the order I added them and not the sort order.
Frustrating to lose all that work every time.