I've just got a Nexus 7, and have a problem with the USB link. The Nexus internal storage shows up in Windows Explorer (XP), I can navigate through the folders, and transfer files to the Nexus. But files that my application writes to the Nexus file system can't be seen. These are .txt files, and I can see them using a file explorer (FX) on the Nexus, and I can send them out to Dropbox (and read them, so they are not corrupt). But I would really prefer to be able to drag and drop from the Nexus to the PC over the USB link in the usual way. Anyone else had this problem, or have ideas about what is going on? Thanks.