I'm completely stumped. I installed GPO5 on my new computer, which is the one I use for serious work. I use my old one for running demos and the like. So, on the old one I recently installed GPO4, so I could demo Sonar and Reaper. Fine. I have not used this computer since getting GPO5. Did not install GPO5 on it. Today I opened up a piece I was playing around with on Reaper, and, Behold, GPO5! The Aria is the new one. OK, it updated itself, right? That happens. But then I see that the GPO5 library is actually available, when I have not installed it on this computer, and when I load an instrument, it loads. I tested it with the Garritan Orchestral strings, which GPO4 does not have. And it loaded. how can this be? I do have the GPO5 download on an external drive that is connected, but that drive is turned off. Now, this is not a problem, just a puzzler. I'll try not to lose sleep over it, but it is really weird. This should not be possible. I'm hoping that SysEx John has an answer.