Sgd-r20 problem

It's tough to say what the problem may be. If I understand your description, it sounds like the door is dragging on the track/threshold. Is that accurate? If so my first guess would be an issue with the rollers. Either they're too worn and aren't functioning properly, or they need to be adjusted.

You asked if you're missing screws, but that's not really something I can really know. You'll have to check the existing hardware. Most patio door rollers can be adjusted by turning a screw that sticks out of the bottom corners of the door. Check there first and see what you can determine.

Lubrication also can't hurt. It's always a good idea to clean lubricate the track and rollers first and see if that helps. Worst case scenario is it does nothing and your rollers are still broken, which puts you at square 1, but at least now you have a clean track. However based on what you described it definitely sounds like the rollers need to be adjusted to lift the door off the track, or replaced entirely.

Our site doesn't have the ability to accept videos, unfortunately. I also have not received and photos from you at this time.

Based on your description of the problem, it sounds like your rollers may be missing their adjustment screws altogether or they're so damaged that they're non-functional. Either way the result is the same: you will need to replace your rollers.

At this stage you will need to take the doors down and remove the rollers so that you can take a few good photos of them. I can use those to make a recommendation. I specifically need to see the top end, back end, and sides. You will also want to write down your dimensions for review.

The video below will go into more detail as to how this can be done.