trnsfering to disk -pse 15

If you want to move them to a new location that the Organizer retains so it can find them, use the File > Move command. On the other hand, if you want to create a copy of the pictures somewhere, use File > Export as New File... In this case, the Organizer relinquishes all responsibility for managing the exported images, and the Catalog is unchanged. It seems that you want to use the Export command, since you mentioned a thumb drive.