I've got an external USB hdd that I wish to use entirely as a TrueCrypt volume. There was one pre-formatted partition, so I'm trying to erase that with Disk Utility. But no matter what I do or try, whenever I Erase the partition (or the entire disk), it keeps automatically re-creating a new partition.

How do I just erase the partition, without recreating one, thus leaving the entire disk empty (i.e. without even one partition) ?

  • Could you edit the post to show what diskutil list disk1 (or whatever number your USB drive is) so I can get you a good command to use? Also why not use Disk Utility to make the partition marked as free space?
    – bmike
    May 12, 2015 at 16:15
  • 3
    Your issue aside - why would you want to use a solution that is no longer supported & has acknowledged security issues? truecrypt.sourceforge.net & truecrypt.sourceforge.net/OtherPlatforms.html contain only instructions to remove TrueCrypt in order to use built-in solutions.
    – Tetsujin
    May 12, 2015 at 16:16
  • @bmike diskutil list disk2 says: /dev/disk2 #: TYPE NAME SIZE IDENTIFIER 0: FDisk_partition_scheme *2.0 TB disk2 1: DOS_FAT_32 UNTITLED 2.0 TB disk2s1 (sorry for crappy formatting, can't insert linebreaks in comments)
    – RocketNuts
    May 12, 2015 at 23:49
  • 1
    @Tetsujin: at the risk of going off topic here (altough I would happily discuss further about this in a chat), the so called 'acknowledged' security issues are highly debatable at best. Most likely scenario is the original truecrypt developers have been put under pressure (by NSA and similar organizations) to spread false rumors on security leaks, especially as they recommend a proprietary, closed source alternative from an American company (bitlocker) which is therefore almost guaranteerd to have backdoors.
    – RocketNuts
    May 12, 2015 at 23:58
  • @Tetsujin Instead, I rather put more trust in the independent and verifiable truecrypt audit which clearly states that, some minor coding issues aside, truecrypt is absolutely safe. I'll prefer that over bitlocker any day of the week. Think about it: if truecrypt would actually be safe, in whose best interest is it to spread FUD about unknown security issues? And as for built-in solutions, I intend to access this disk on both OS X and Windows. And besides, unlike TrueCrypt, neither I nor anyone else can verify Microsoft's bitlocker or Apple's filevault.
    – RocketNuts
    May 12, 2015 at 23:59

2 Answers 2


To remove all entries from the GPT and MBR tables, open the Disk Utility application and do the following.

  1. Select your disk.
  2. Select Partition tab.
  3. Set Partition Layout to "1 Partition".
  4. Set Format to "Free Space".
  5. Click on the Option... button and select "Master Boot Record".
  6. Click Ok to close the pop up window.
  7. Click the Apply button.

The image below was made just before clicking the Apply button.

  • The Partition Layout UI is not present in OS X 12.1 it seems. Dec 26, 2021 at 0:30

If you are comfortable with command line:

  1. Run diskutil list
  2. In the output, identify the disk you want to erase all partitions from. It will be something like diskN (N being a number).
  3. Run sudo diskutil unmount /dev/diskN. It might say diskN was already unmounted or it has a partitioning scheme so use "diskutil unmountDisk" instead, no worries.
  4. Run sudo diskutil unmountDisk /dev/diskN. It should say something like Unmount of all volumes on diskN was successful.
  5. On the command line type sudo dd if=/dev/zero of=/dev/diskN bs=1 count=1024, double-check you have replaced N with the correct number as an error here could be catastrophic, then run.
  6. Veracrypt will now be able to create an encrypted volume on that entire disk (I just tried now).

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