Liner pulling out of track

[Vinyl_Guy]

Here's a little bit of anatomy. Sorry it's not to scale or exact, but it is from memory.

Left is a cross section of what is going on, far right is a more detailed image of how the liner holds in the "track". Assuming you have the coping I think you have (CP-2 or very similar).

The lone image in blue is how you should be trying to fold the liner in on itself, as you pull on it.

A proper build should hang the coping out over the edge of the pool wall slightly (less then a 1/2 inch more then an 1/8th, depending on foam thickness). This is to make room for a wall foam, and if no foam is installed, at least to give the liner some room so that it doesn't more easily lift out of the "track". If the very front of the "track" portion of the coping is flush with the wall, it's going to be a lot harder, if it's even slightly back from the front top corner or edge of the wall, it might be a nightmare.