A reformat is a reset through your computer that erases all information and restores your device to its factory defaults. Reformatting is simple.
On a Mac:
Formatting is easy. Go to your applications and open the utilities folder. Find the application called DISK UTILITY. When you open Disk Utility, select your device and you will see the options to First Aid, Erase, Format, RAID, Restore.
First, Select First Aid. Click the button that says "Verify Disk". After it finishes verifying, Click the Button Below it that says "Repair Disk".
Second, When The repair program is finished running, Select the Erase Option.
Third, Use the drop down menu next to FORMAT to select your desired format. "MS-DOS (FAT)" if you want to be able to use your device with both windows and Mac, or "Mac OS Extended (Journaled)" if you will be using it only on your Mac.
When it finishes, if it doesn't mount to the desktop, open Finder and check if it is showing up under devices in the sidebar. If it still does not work please let us know and we can see if we can help you further.
On a Windows:
Depending on the device you own, you may not have the reset option. If your computer recognizes the device, formatting is very simple.
1) Open My Computer and right click on the device.
2) Select the "format" option.
3) Select "FAT 32" under the File System and make sure Quick Format is not selected. (If you are not sure, just leave all the selections as default.)
4) Click on the format button at the bottom of the window, and follow the prompts until it has completed the format.
5) Eject the device and test it with several recordings.