How to fix a sliding door that has come off its track?

To fix a sliding door that has come off its track, whether patio sliding door or sliding closet door, you need to lift door back into track after cleaning and inspecting rollers, which is simpler than garage door off track and can be DIY. For patio sliding glass door, first open door halfway and have helper support weight, as door is heavy, 50 to 100 pounds, with glass. Lift door up into top track first, tilting bottom toward you, then set bottom rollers onto bottom track, ensuring rollers seat in groove. If rollers are damaged or dirty, remove door fully by lifting up and pulling bottom out, then lay door on sawhorses and inspect bottom rollers for wear, dirt, or broken wheels; clean rollers with cloth and vacuum track to remove dirt, leaves, and debris that cause derailment, and lubricate rollers with silicone spray, not oil that attracts dirt. Adjust roller height screws on bottom edge to raise or lower door for proper clearance, turning screws clockwise to raise. If track is bent or dented, straighten with pliers or replace track costing 20 to 50 dollars. For closet sliding doors, lift door up and angle bottom out, then reseat. After reseating, slide door back and forth to test smooth operation. If rollers worn, replace roller assembly costing 10 to 30 dollars. Keep tracks clean and avoid forcing door, and consider installing track cover to prevent debris.