I use an external hard drive frequently and when I try to open a file, a jpg for instance, the Mac always tries to use Preview, this is after I've opened the image app (iView), gone to 'Get info' and reconfigured it to make the image app the default app for jpgs. It'll work fine then until I shut down the ext hd. The next time I open it, it reverts to wanting to use Preview. This seems to be the case for all apps and files loaded onto the ext hd. In fact, when I open the ext hd and try to open iView, it takes two or three attempts before the app opens. What do you think?