So, I originally posted this in the OS X forums, but after nearly 200 views and not one single response, I'll try again here since the problem is in a MP. Purchased a 16GB Patriot Exporter USB flash drive to use it for OS installation / portable booting on my 2009 MP running OS X 10.6.8... When I format it in my 2009 MP to Mac OS X Extended (Journaled), the size remains basically unaffected at around 15.5GB free. BUT... when I partition it as GUILD (1 partition) to make it bootable, the available space reported by disk utility drastically goes down to around 10GB. The weird thing is that Disk Utility reports what seem to be inconsistencies in the available space - see the screenshots below. I've tried everything - reformat the drive with Patriot's low level format tool in windows to bring it to its original settings, empty the trash, secure-erase it with DriveGenius... nothing seems to work. I wonder if I'm doing something wrong, or if the drive is defective... >5GB lost space is too much I guess... any ideas? Thanks!