How to Format an External Hard Drive

January 27, 2009 | | Comments 176

Updated Version of This Article Now At

Please click here to read the latest version of this article and see the new video tutorials on How To Format An External Hard Drive at


Filed Under: (11) FAQ


About the Author: David Marx teaches digital photography workshops and Adobe Photoshop Lightroom training classes. David is an Adobe Certified Expert in Photoshop Lightroom and in Adobe Photoshop. David has lead workshops and seminars for the Rocky Mountain School of Photography, the American Society of Media Photographers, FirstLight Photography Workshops, and he teaches annually at the world-famous Blackberry Farm Resort. For more information on his Photoshop Lightroom training seminars and digital photography field workshops please visit You can also follow daily updates and see new images from David on Google+.

RSSComments (176)

Leave a Reply | Trackback URL

  1. Tyler says:

    P.S anyone who is doing this for a TB make sure you have plenty of time…he wasn’t joking when he said it will take a long time…its only at 4%…it’s been going for nearly 40 minutes.. o.o

  2. Tyler says:

    Hey, thank you so much, worked great! my only comment is that I used this tutorial to format a external harddrive that had content on it & was locked (I was using as a PVR with my Bell box) soo I had to right click on the each partition and select ” delete volume ” before I could format the entire drive!

    All good though, thanks! (:

  3. maya says:

    My hard drive keeps saying needs formating but I have so many things on it can you please tell me how to do this without erasing everything

    • David Marx says:

      Dear Maya,

      This sounds bad. My advice is to copy everything from that disk to another and then reformat. Reformatting will wipe the disk completely clean. If the data that you might loose is super important perhaps you should seek out professional assistance before things get any worse.

      David Marx

  4. As great as your advice is, you made a crucial mistake and it cost me everything. You assumed that the people who were following you on your how to format your external hard drive were using a blank disk. I was following along with an external hard drive that was full and had all my important things on it and the tutorial said to click the button and then, after that, it said that it was going to wipe out my entire drive and that was okay because the guy using the tutorial was using a blank drive. It wiped out everything on my drive. So, thank you, your carelessness wiped out years of hard work. I am only writing this so you can fix it so someone else doesn’t get completely screwed.

    • David Marx says:

      Dear Deborah Pryor,

      I am sorry to hear that you have lost important data. May I suggest that you set that drive aside right now. Even though the disk has been format the data maybe recoverable with the right software. Data can still be recovered as long as you do not write fresh information over top the old stuff.

      I do apologize too. I hoped that this paragraph makes it clear that formatting wipes a disk clean. “Format and partition your new disk immediately, before you start using it for backup or for additional file storage. It is essential that you do this right away, before you start using the drive, because the formatting process erases everything on the external disk.”

      I would like to think too that your operating system’s warning that all data on the disk will be removed would also cause you to reconsider. Again, I beg you set that disk aside and investigate your data recovery options right now before any further damage occurs.

      David Marx

  5. deedubb says:

    An excellent video presentation and audio instruction 10 out of 10; go to the top in your class !!!!!!!!!!!!!!!!!!

  6. Sandy Henry says:

    I am very new at e everything when it comes to a Mac computer. I just got an external hard drive.once, I backup my information, how do I. retreve information from my external hard drive ata later date. thank You

    • David Marx says:

      Dear Sandy Henry,

      The recovery method varies from backup utility to utility. With programs like TimeMachine, or Carbon Copy Cloner, the recovery method might be as easy as drag and drop. With other software you might need to select the appropriate files and then use a restore button.

      Hopefully you will never need to retrive files from the backup drive but with no backup there is no chance that your data will survive if a disaster strikes.

      David Marx

  7. Vito Maraula says:

    Hey great videos dude!

    Question: Im trying to reformat a USB flash drive as you have prescribed in the vids, but when I partition or try to erase it a message comes up saying ‘can not erase unknown error: -20′

    What ever is going on is bummin’ me out superbly, please help!


    • David Marx says:

      Dear Vito Maraula,

      It sounds like either the disk is in a file format that your computer cannot access or that the flashdrive is broken. If you are on a Mac then what happens when you plug this drive into a PC? If you are on a PC what happens when you connect it to a Mac? Either way I suspect you will need a new flashdrive.

      David Marx

  8. Gaurav Dubey says:

    the video was really helpful…..

  9. Atli says:

    My external hard drive is full of vital information. Now, when I plug it in, my laptop tells me that I need to format it before using it. This won’t do anything to the files on it, will it?

  10. Jerry says:

    Hi- Mac OS10.8.2- I am about to change backup from one external OWC Mercury Elite Pro (1T) to a RAid 1 system for redundant backup. I am planning to use the OWC as a backup for just my photos via Lightroom 4.2. Do you recommend reformatting the drive or just deleting it and start backing up to it? I only use a Mac OS, not cross contamination, as it were. Thanks-Jerry

    • David Marx says:

      Dear Jerry,

      In this case I would recommend reformatting. Reformatting the older OWC will wipe it clean and refresh the disk permission. When reformatting I suggest using the Partition option to create 1 partition using the GUID option.

      David Marx

  11. Dawn Sutcliffe says:

    simple, clear, easy to understand.
    So grateful!

  12. Thank You, you saved me so much grief! I’ll stay connected for more great advice!

  13. Euno says:

    As far as it actually “zeroing” the hard drive. If has only had one pass of zeros written to the drive it is easily possible to recover all of the data on the drive. If you really want to permanently zero the drive you would have to do a multi-pass on “preferably” linux. I feel formatting the drive like that provides no extra security.

  14. Appreciate the info on the above short video. I just tried to format a new 2Tb Seagate for my MacBook and the info I first Googled didn’t work, which was to basically ‘erase’ the drive(it came up as an error). Trying your ‘Partition’ method worked like a charm however. I verified it by adding a video clip to the new drive and then imported it into iMovie as a further check. All worked great and I’m off and running now!

    Do have one question tho: As a precaution, I first copied the folders that were on the new unit(which was meant for a PC), to a Desktop folder on my Mac just in case, but do I even need to put those back on there now or even keep them? Thanks!

    • David Marx says:

      Dear BaronDWoods,

      If the programs that came with your new hard drive are intended for use on a PC then you do not need to keep them on your desktop or on the external drive. If there is software in there that you think you might someday want, and if it will run on a Mac, then keeping that folder might make sense. I say might because I suspect that whatever Seagate gave you with the disk you could download from their website at anytime.

      David Marx

  15. adam mackie says:

    i Use an external hard drive and have been using it (formatted for the last 4 years) i plugged it in to use and it says it needs formatted, but here is the problem i have all my photos, music already stored on the drive, what cani do to save them.

    • David Marx says:

      Dear Adam Mackie,

      Sorry to hear about your external drive troubles. Usually when that kind of message appears it is a sign of serious drive trouble. The data on the disk might still be useable but then again it might be a loss. How solid are your backup plans for this drive?

      David Marx

  16. corrie says:

    hey Dave,
    just wondering if you could give me a how to run down on tranfering music files from my gf’s mac to my pc using a lacie rugged mini 1tb hard drive?…. having trouble please help?

    • David Marx says:

      Dear Corrie,

      Sorry but Adobe Photoshop Lightroom is my specialty. I assume that her music files are like any other type of data and that you can copy them from your gf’s mac to a cross platform formatted hard drive and then copy from that disk to your pc. The question is will they play or are they in a content protected format? This is unfortunately out of my area of expertise.

      David Marx

  17. simon whalley says:

    Thanks, this is the best advice i have found to format external hard drive which was causing me a hassle.. thanks again!!!

  18. Sara says:

    I got an iMac back in early 2010 but recently had to replace the hard drive. When I got the computer, brand new, it came with iWork on it. When I replaced the hard drive, all that disappeared. My question is, is there a way to get it back since I didn’t buy it?

  19. Ron Putnam says:

    Do you still recommend the Paragon NTFS for Mac? I recently started doing work for a studio that is all PC and I can’t figure a way to transfer files back and forth. This article seems a bit old so I was curious about your current recommendation.

    • David Marx says:

      Dear Ron Putnam,

      If you have a spare external hard drive then going the exFAT route might be cheaper and easier. exFAT compatibility is built into all of the latest operating systems and it can be added to older versions of Windows for free. The only catch is that backup programs like Carbon Copy Cloner (Mac) or Acronis (Pc) are not going to like writing to an exFAT drive.

      David Marx

  20. Looks like youve got a great blog here, I love all the interesting information and advice!

  21. Pam says:


    I have an Apacer AC202 500GB external HD. As in one point of time my drive stop working properly I decided to reformatted. I follow up the steps on the tutorial but not along after the formatting process start its seems that the HD follow asleep and a message ” formatting cannot be complete ” pop up. If I do a quick format there isn`t any problem and the HD is ready for a use in a seconds but I`m sure that I`ve got some bad sectors and I`m afraid that the quick format will not fix them. I hope that someone could give me an advise of what to do. By the way my laptop is using windows 7 as OS.

    Thanks Pam

  22. Laura says:

    Hi David,
    So I had my hard drive formatted for my PC and then I needed if for a class and formatted it to a Mac. But now I want to re-format it to for my PC. How do I go about doing this? Is it possible to reformat it so it works for my PC again? I know I might loose everything that is currently on my hard drive but that is not a problem. Any kind of direction would be helpful! Thanks

    • David Marx says:

      Dear Laura,

      If you are not afraid of loosing the data that the disk contains then you can go ahead and format it again. Formatting it using the NTFS file structure is probably the easiest and will make it the most PC compatible. Formatting it exFAT, or installing additional software like MacDrive on your PC, might be a good option too. With an exFAT drive or with MacDrive the disk could be usable on both platforms.

      David Marx

  23. Victoria Morgan says:

    Hey, I just needed some simple formatting instructions, and it your tuition was great! Thanks heaps.

  24. Zanty says:

    I just watched your video how to format a drive on windows because I just wanted to make sure I was doing everything right and my external hard drive will not format. I have a 2 TB seagate that I used a few time in the past 8 months. About a month ago I plugged it in and one of my computer hardly recognize the drive. After all the attempts to open the drive I gave up and decided to format it. when I try to format it, nothing happens. I go through all the steps you went through on your video but it doesnt do any thing. I’ve tried windows XP, windows vista and windows 7. I’ve left it hooked up “formatting” for up to 10 hrs and nothing changes on the computer management window.
    Can you help me or is my external hard drive completely dead?
    I hear something moving inside and it gets a little warm, but I have noticed that there is a bump on one of the big flat surfaced (my external hard drive lays flat, does not sit up tall). Don’t know what that means.


    thanks for your help in advance,


    • David Marx says:

      Dear Zanty,

      I am afraid that I can only guess at your hardware issues. I would try reformatting the drive one more time using the quick format options. If it doesn’t respond promptly I think I would give it up for dead. It might be just fine but I tend to be very cautious. At the first sign of trouble I usually move on. Replacing an external hard drive is relatively inexpensive. Replacing all the files that a failed disk used to hold might be very costly! See Professional-Grade Backup Plans for more advice on how I protect my files from total loss if a disk fails.

      David Marx

  25. RayR says:

    I was dieing trying to format my new WD Green 1T in an external shell on my Dell XPS. It would say read error, or st stop seeing it even in Manager. Then I realized it wasn’t loading the drivers correctly…no matter how many times I tried! This article reassured me that I wasn’t missing anything. It’s great. Thanks.

    BTW, I put the drive on a Gateway desktop (both running Windows 7 4x) and it immediately said Drivers Installed Correctly. Would you like to Initialize? And Would You like to Format this drive? Easy as 1,2,3.
    Any thoughts on what would block the Dell from loading the drivers? Antivirus or Malware program? The Microsoft USP mouse in a different port I am stumped!

  26. NumNum says:

    This video was very helpful. Thanks for posting.

  27. David Hayes says:

    I am far from being a whiz at the computer so I need all the help I can get. I have searched around fairly often trying to learn about this machine and this page and tutorial is the best I have seen and oh joy I could understand it . THANK YOU

  28. Denise says:

    THANKS!!!! So helpful, just brought a drive back from the dead with this:)