Weirdness with SanDisk compact flash

Question

I just purchased a SanDisk usb flash drive. I inserted (into the [usb 1] port on the mac keyboard), and formatted with Mac OS Extended/Journaled, I reboot and get: "The disk you inserted was not readable by this computer", it then gives the "ignore" or "eject" options, I click "ignore" and it mounts on the desktop just fine.
If the thing isn't connected, and I then insert the flash drive, the drive mounts but it is then followed by a CD icon popping on the desktop with the name "Untitled CD" -- !!??
Recap: Reboot with the flash drive inserted, I get the warning. Insert after the computer is up and I get no warning but the CD icon appears along with the regular flash drive icon.
I tried this all on another partition with the same results. Also, I inserted a different "Lexar Jump Drive" without any of the aforementioned problems.
Can anyone give me a clue?
Could the SanDisk somehow not be compatible with the Mac?
I'd appreciate any input.
TIA,
Geoff

Answer 1

Hi, Geoff.
1. You wrote: "I just purchased a SanDisk usb flash drive."What specific model or model number? Given how many they make, that's important information relative to your question.
2. You wrote: "Could the SanDisk somehow not be compatible with the Mac?"It's possible the firmware on the specific UFD (USB Flash Drive) you have is designed for PCs. It may have specialized firmware for other functions, such as security, that do not work with Mac OS X or Macs. The anomalies you are seeing do seem strange.
I recommend you contact SanDisk. When you have problems with third-party hardware or software, it is often more expedient and effective to start with their Web site and their support. You paid them for it, they should support it. I'd at least recommend you look at their Self Help.
3. If you want to continue troubleshooting before contacting SanDisk, you might try reformatting the UFD. When you formatted the UFD, did you select the device, not the volume on the device? For example, In the column on the left in Disk Utility, you might see something like this:<pre>38.2 GB IBM-DTLA-307045
Macintosh HD</pre>The first line ("38.2 GB..." etc.) is the disk, the actual hard drive itself, also known as the device.
The second, indented line (Macintosh HD) is your Mac OS X startup disk, aka your boot volume. This is a volume on the device. Volumes -- partitions on a disk -- appear indented below the disk in Disk Utility. If the device has multiple partitions defined on it that Disk Utility can recognize, there will be multiple volumes listed below the device. The UFD may also have a hidden partition that Mac OS X cannot see, such as software or firmware related to special features, like security.
With your UFD, select the device for erasure using the Erase tab of Disk Utility. You may also want to add one of the Security Options available from the Erase tab before formatting, e.g. Zero Out Data, to assure there are no "bad spots" in the flash memory, akin to bad sectors on a hard drive.
Good luck!
Dr. Smoke
Author: Troubleshooting Mac® OS X