@Lars Aam, unfortunately I don't have enough Karma to comment on your answer however that is not acceptable. We have days when we manufacture hundreds of products daily. Creating a manual transfer for each individual serial number that have failed the testing is just... not good enough from a quality point of view. It interrupts the testing because that person has to manually address the failed product. Plus the operator should never leave the Work Order screen untill he/she is done and/or the shift ends.

This adds extra admin work, more opportunities for variation and more waste in terms of time. All red flags from a Lean & 6 Sigma point of view.

Is there no way to automate the Manufacturing process to automatically create a transfer from Post Production to Repair In with the serial numbers of the failed products when the WO is done? In this case, the manager (me) can confirm the transfer and the operator doesn't have to waste time on it.

As far as I know there is no automatic transfer possible for failed products.  Manually you can transfer from stock to a Repair location.  Where it is not avaible for sales / delivery.