Just now I got the garage door to replicate the problem: it got stuck while opening at about 5 feet up. I hit the button on the wall again, it closed, again and it opened to about 3 feet, again, again, and it stuck at about 1 foot. Then it opened all the way and apparently returned to normal ... for now. I thought this might clarify what the problem was for you garage door experts.

On the back of your motor unit you will find the 'up force' control. Increase this a 1/4 turn and see if it doesn't cure your problem.

This may not apply to your situation, but if you have a chain driven opener, check the chain to see what kind of grease is on it. The seller of my house put this thick black grease all over mine. The grease would get harder or softer depending on the weather which caused the door to not close properly. Adjusting "down force" helped, but I had to crank mine all the way to max.

I checked a few forums and they told me that the proper grease was white lithium.

Your problem seems a bit different, but I thought I would share anyway :)

Mine has a rubber belt. I have now adjusted the UP force and it seems to be working fine now ... even without me cursing!
Many thanks,
Don