From my understanding of it (I am just an user), you shouldn't install two versions concurrently. At least not a beta and a regular version. You better uninstall both versions, and install just the later. Keep the old version setup file around in case there is problem with 4.5.1, although in my experience it works great! Your registration info and all your settings (FTP, stationeries,etc) should not get deleted upon uninstall. Just to make sure, do backup them before (it's a good idea anyway to backup them, after all you might have a lot of keywords and servers etc). The settings are AFAIK stored in your home folder, in Application Data/Camera Bits/Photo Mechanic (or perhaps Camera Bits Inc, I think this changed between 4.4 and 4.5). You can also backup them directly from PM, If I remember correctly. Hope this helps, Frantisek