Hi Tanja

Yes there is an easy way to fix this, and it will even make sense once you read this.

Create a new cash batch and re-enter the check to the wrong customer, this time using a slightly different check number (e.g. 1234A instead of 1234) with a NEGATIVE amount. Then go to each invoice that the original check was applied to and apply this check to it in the negative, thereby bringing the outstanding balance back to where it should be. Save the entry.

You are now back at square one. Now enter the check properly. The total of the cash batch should be zero, so it will have no effect on the GL.

Steve