Bases loaded with (1) out B1 hits a fly ball to left field and all runners take off. Left fielder makes the catch for the (2nd) out. All runners are returning to tag up, the left fielder throws the ball to 1st base to get the runner out but the runner on 3rd scores before the 3rd out is made. Does the run count?

If the runner on third properly tagged, the run counts. Once the fly ball was caught, there is no force, the runner can return to first. It is an appeal play. The out is registered when the appeal is completed.

Ed H

If the runneer on third didn't tag up and scored before the third out, score the run. To negate the run the defense must get a fourth out appeal before they leave the field.