One of the most consistent recommended practices throughout the history of App-V sequencing is to always sequence on a clean sequencer. Starting with App-V 4.6 SP1, a detector was put in to warn users if they were about to sequence on a machine where a previous package was sequenced.
When the App-V sequencer is installed, it will create a registry key called ReadyBit located beneath HKLM\Software\Microsoft\AppV\Sequencer and set this value to 1. As soon as a sequence begins to go forward (creating a PVAD, Package Name, etc.) this bit will be set to 0 to inform the sequencer that we are no longer working with a clean sequencer.
So, the obvious next question would be, should we be manually resetting this bit. Only in certain circumstances. Let’s say you gave an incorrect package name or specified the wrong PVAD and went forward with the wizard and accidentally began monitoring. You had yet to install any binaries but you realized you made a mistake. Is there another option other than reverting to a previous snapshot of the virtual machine? What if you were doing this on a physical workstation? Yes, you can exit out of the sequencer, set that registry setting manually, and restart the sequencer and not have to worry about having that warning pop up during the computer preparation stage.
Please note that this is the ONLY time I would recommend doing this.