10.4: A fix for non-mounting USB drives in 10.4.10

Jun 29, '07 07:30:00AM

Contributed by: wallybear

After updating my Mac to OS X 10.4.10, my external FireWire/USB2 drive didn't mount any more (if plugged in via the USB2 port). I thought about an interface failure specific to my enclosure, but searching on the web, I saw that it was a common problem for 10.4.10 users with Intel Macs and external enclosures. Moreover, I tested the drive on another Mac with 10.4.9 and it worked flawlessly. So it was a problem with the 10.4.10 update.

The only solution found until now was downgrading to 10.4.9 again, but this is a real pain. I was ready to use Pacifist to replace the new USB kernel extensions with the older 10.4.9 ones. But before doing this, I wanted to check if I could force the drive to mount in some way, and accidentally found the workaround.

I used System Profiler to list USB devices and get the VendorID/ProductID of the drive; it was listed amongst my other devices. As I needed some more device information, I launched USB Prober (included with Apple's Xcode Developer Tools) and ... the drive mounted on desktop! Apparently the polling that USB Prober does on USB devices causes OS X to realize that the device is a USB Storage Class product and finally mounts it. I tried several times and it always worked: USB Prober makes the drive mount.

So, if you have the same problem with your external USB device, here's a workaround until Apple fixes it:

  1. Plug your drive in
  2. Launch USB Prober (/Developer » Applications » Utilities » USB Prober)
  3. After the drive mounts, quit USB Prober
That's it! The only drawback is that you must have the Developer Tools installed (as USB Prober comes with them). If you don't want to install all of the developer tools, you can simply extract the application from the installer package using Pacifist. Hope this helps!

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