So, I have a Galaxy Nexus. And I'm a Mac user. Installed the Android File Transfer app like you're supposed to.
It was working fine and I was on my way to transferring a few gigs of music using MTP. But it failed and threw an error message.
From that point onward, the file transfer app has thrown an error every time I've opened it. The app loads the Android filesystem, and you can see it, but an error message pops up: "Can't access device storage. If the device's screen is unlocked, disconnect its USB cable, unlock your screen, and then reconnect the USB cable." This message steals focus and though I can see the mounted file system, I can't do anything but quit the app.
I've tinkered with the USB developer debug option and all its siblings, checked the cable, restarted everything, pulled the battery out, everything.
It seems like there's some corruption, or something along those lines. If there were a safe mode, or reboot, or something along those lines, I would give it a try. But all I can think to do now is factory reset the Nexus, and I'd really like to avoid.
Any thoughts, anybody?