What is a void bet?
A void (or “non-runner”) bet is one the bookmaker cancels and refunds because it can’t stand — a horse that doesn’t run, a postponed match, or a market settled incorrectly. Your stake is returned, and in an accumulator the void leg is simply removed.
Example
In a 4-fold acca, if one selection is void it drops out and the bet runs as a 3-fold on the remaining legs at their combined odds.