On the v2 devices, the Sansa has a different processor and no “16 MB FORMAT” partition. To restore the file structure to FAT32, the v2 can self-format via going to Settings > Format > Yes. this will reformat the device to FAT32, but it does clear all existing music files from the device.
If the device will not espond, allowing you to navigate to Settings on the main menu, you can first try resetting the device by holding the Power button depressed for about 20 seconds, release the button, and try powering up again.
Alternately, if you plug in to a Windows PC, you can connect, navigate to the device, right click on it, and select Format. Use the basic Format function and not “quick format”, this is what I’ve always found to work best.
Note, this is for the later v2 devices. You can format the v1 this way, as long as you are not connected in recovery mode. Formatting the recovery partition removes critical data. For the v1, earlier player, use the Sansa.fmt file trick in the top post here.
To verify if you have a v2 device, this is quite simple. When powered up, you will see a SanDisk logo with reflection, and a blue sansa logo pops up moments later.
microsansa
