How to clean up a Thumb Drive
Mac Tip #350, 06 August 2008
Many people use thumb drives — those tiny ‘sticks’ you plug into a USB port — for storing backups of important documents, and they’re great for that purpose: quick, easy, convenient. Copy files to the drive, drag files from the drive, add, delete — it all takes but a moment.
When things go wrong
Until, maybe, something goes wrong, as a friend found recently when one file claimed to be corrupted, and the daily backups wouldn’t complete. This problem isn’t unique to thumb drives, by the way — it can happen any time to any storage medium.
In the screenshot my No Name thumb drive has a bunch of files on it.
How to reformat a thumb drive
In my friend’s case we did some troubleshooting and then decided to reformat the thumb drive. Here’s how to do that.Start up Disk Utility. You should find it in the Applications — Utilities folder. The Disk Utility window opens and displays a list of disks in the left-hand column.
Plug in the thumb drive you’d like to reformat. It should also show up in the list of drives.
In the screenshot you can see a list of the internal hard drive and DVD drive on my Mac. My No Name thumb drive is listed, and I’ve selected it in the list. Click on the thumbnail images in this post to see larger versions.
Warning: erasing destroys data
Click on the thumb drive in the list to select it.
Now take great care in the next step. When you reformat a drive it completely erases everything that’s on it.
Make sure you select the correct disk and also make sure you have copies of any files on the thumb drive that you wish to keep.
After selecting the thumb drive in the list click on the Erase tab on the right hand side of the window.
Choose a Volume Format from the pop-up — try Mac OS extended (Journaled), and if you wish, give the thumb drive disk a name.
Double check that you will be erasing the correct disk and then click the Erase… button. An alert appears reminding you that all data will be erased and asking you to confirm that you wish to erase the drive. Click Erase to wipe everything or Cancel to abandon what you’re doing.
My screenshot shows that I’ve selected a thumb drive called 964 MB Ut165 USB2FlashStorage Media and am about to click the Erase button on the alert.
After a few moments the disk is wiped clean. When I look at the disk in the Finder I see that no files remain. In my screenshot you can see the thumb drive now shows up in the left-hand column of Disk utility with the name I assigned it.
If you wish, click the Security Options… button before you erase the thumb drive. Choose from the different methods for erasing, depending on your purpose.
If all you want to do is wipe a drive you’ve been using so you can start fresh choose Don’t Erase Data, or Zero Out Data.
If you’re cleaning up a drive someone else gave you, to be sure there’s nothing nasty on it, or to give the drive to someone else, choose a more secure option such as 7-Pass or 5-Pass Erase. The more secure the option you choose the longer it will take to erase the drive.
By the way: if you want to reformat a memory card to be used in a cellphone or camera first check the manual and help files for that device. You may be best to reformat the card in the camera or cellphone itself so it uses the correct formatting options.