Open the garage door and use a flashlight to inspect the tracks on both sides of the door for debris, dust or stones that could cause the rollers to catch. Check that the rollers are not worn: They should be round without flat spots. You can lubricate the rollers with a few drops of automotive engine oil to ensure they operate smoothly. Close the door and inspect it again, using a small stepladder if necessary.
A loose or damaged hinge is a common cause of garage door popping. Ensure each hinge is in good shape: The roller bolt should be perpendicular to the track, and the hinge must be securely fastened to the door. Use a socket or box wrench to tighten any loose bolts and a rubber mallet to correct minor bends in the door panels. Note more extreme damage that would need to be referred to a professional repair company.
If you have an electric garage door opener, check that the problem isn't with the opener itself. Consult the opener's user guide to disconnect the drive chain from the door, then open the door manually. Since a garage door can weigh hundreds of pounds, it can be helpful to use an assistant for this test. If the door opens smoothly, it might be time to replace the garage door opener. Otherwise reconnect the opener to the door.
Many garage doors use large torsion springs to assist in opening the door. Over time, the coil of a spring can lock, preventing smooth operation and causing a popping noise. With the door open, lubricate the spring generously with motor oil and a clean, dry cloth. If the problem persists, it's time to consult a professional to unwind, lubricate and rewind the springs. Homeowners should not attempt this step themselves, as removing or modifying a torsion spring could result in injury.