Off track means a roller has come out of the channel that guides it, so part of the door is no longer being held in line. You will see a panel sitting at an angle, a top corner leaning into the garage, a visible gap between the door edge and the track, or a wheel dangling in the air. The opener normally stalls at that point, and it is the right thing for it to do. What matters next is understanding that the track is almost never the thing that failed.
Cause one: a nudge nobody mentioned
The commonest cause is also the least dramatic. Somebody backs gently into the closed door, or clips the bottom section pulling into a tight driveway. Nothing breaks, no marks worth reporting, and life goes on. What has actually happened is that the foot of one vertical track has moved a few millimetres out of plumb, or the lowest roller bracket has taken a small bend. The door keeps working for weeks or months, running a little tighter on that side each trip, until one ordinary morning the wheel climbs out. Narrow single car garages on the older streets of South Oceanside and Townsite, several of them opening onto an alley with no room to line up square, collect more of these than the wide driveways further east.
Cause two: the counterweight let go
The other route is quicker and does more harm. A lift cable parts, or a spring breaks and one cable goes slack, and that corner drops while the opposite corner stays where it was. The door racks across its own diagonal, the rollers on the low side are pulled sideways out of the channel, and the top section can twist hard enough to split along the hinge line. This version arrives with a bang and it does not settle down on its own. It is also the version where the door is no longer counterweighted, which changes everything about how you treat it.
Why putting it back is not the repair
Here is the part owners find frustrating. Lifting the rollers back into the channel fixes the picture and leaves the reason untouched. If a bent bracket or a track out of plumb caused it, the door will climb out again within a few cycles. If a cable caused it, the door is going nowhere until the cable and whatever broke alongside it are dealt with. A real realignment is a sequence: unload and clamp the door, seat the rollers, check both tracks for plumb and for spacing against the door edge along their whole length, straighten or renew bent brackets, inspect every hinge for a split at the barrel, then test the balance and run it. The part that actually took the damage is usually a roller or a hinge rather than the track itself.
The crowbar does most of the real damage
A large share of the cost on an off track door is created after it came off, during the twenty minutes somebody spends trying to persuade it back. A bar or a big screwdriver against a panel edge multiplies your force many times over and the skin is thin, so what follows is a bent track flange, a creased section, a torn hinge and a roller stem pushed clean through its bracket, all of which now have to be replaced too. There is the weight to think about as well. With a cable or spring gone the door is dead weight, and prying at it part way open can bring it down. If you want to do something useful, clamp it: a pair of locking pliers on the track just under the bottom roller holds it still until help arrives.
Check the bottom two feet before blaming anything
Fine sand blows in under the door and settles in the lowest section of both channels, mixed with driveway dust. Packed in behind the bottom roller it forces the wheel to ride up over the heap rather than roll through it, the door starts to shudder through the last foot of travel, and the roller works its way toward the open edge of the channel. Brush that out dry and vacuum it, and do it a couple of times a year if you are within walking distance of sand. That single habit prevents more off track calls around Oceanside CA than anything else a homeowner can do without tools, and it takes about ten minutes on a double door.
What a realignment costs
Realignment runs an estimated $145 to $285, and where it lands inside that band depends on how many rollers, hinges and brackets get replaced along the way. Where a cable or spring caused the derailment, that repair is quoted alongside, so an estimated $135 to $245 for a pair of cables or an estimated $185 to $340 for one spring can appear on the same invoice. Guide bands, not quotes. In practice the biggest single influence on the final figure is whether the door was left alone after it came off, or worked on with a lever first, and that part is entirely within your control.