Usually the only time I have this problem is when I'm using "Super Hero" characters I downloaded from 3DCC. I do believe it's only with pz3 files. I've learned to have my file manager running at this time, and do a search for the needed file. Unfortunately, all too often Poser is looking for a file that you didn't get in the download. Hey, artists make mistakes, and we can't complain if its free.