I have an APC pool cover, and it looks like the rope broke right behind the glider right as the cover was being closed (this is a replacement rope from last year).
My wife didn't notice until the cover was fully closed that the right side wasn't running in the tracks (2nd pic), so now we have one side off the tracks and a small tear where the rope broke.
The good news is that we have an enclosure up (see here), so I'm not worried about the cover just floating there for the moment.
The bad news is that we have an enclosure up, so repair/replacement is going to be an absolute bear (and more cash than I have on hand right now)
[UPDATE] I was originally thinking of trying to open/close without the cover seated in the right track, but looking at how far the cover is sinking tells me that's a no-go.
Main question now is "Is this a rope repair, or a full cover replacement?"
I can afford a rope repair (although it'll hurt)
I can't afford a replacement.