Typically this happens because of springs that have become too loose or cables that are broken.
Garage door falls back down.
If the garage door suddenly comes crashing down and will not go back up this is usually the result of a snapped cable.
Locate the limit switch adjustment either on the back of the opener or behind the light bulb s lens cover.
When the door opens it sometimes falls back down part way.
Also it could be due to springs and cables that have been poorly installed or a damaged garage door track.
When your garage door falls too quickly it is a symptom that something is loose of broken.
Another cause of this problem is poorly installed springs and cables or a damaged garage door track.
If your garage door falls too fast when you decide to close it then the problem may be one of these.
It hits top then bounces back down rather than stopping in fully open position.
Some models have two screws labeled.
This is almost always the result of a dirty.
I have had it serviced twice spring tension and limits adjusted by local overhead dealer but problem persists.
Set a safety ladder under the garage door opener.
By wade shaddy updated december 19 2018 you push the button to close the garage door.
It can also be due to to cables that are broken.
Snapped cables should be professionally replaced before you try to use the door again.