How To Open A File Cabinet With A Broken Lock?

Depending upon the file cabinet model, there's a vertical latch on the right hand side. Find a strong shim that can fit between the door and the case, like a metal ruler, and insert it on the right hand side of the second door.

Try to find the vertical bar, and lift it (there are catches on the side). Keep one hand on the handle for the door, and jiggle the release with your thumb while working the ruler on the right hand side.

If this doesn't work, one other thing you can try is to tip the cabinet backwards as far as you can without it falling over, and then let it drop forward.