I have a 1.5TB USB drive with many important files that I want to give to a friend (they have Windows7) for reading only purposes. thumbscrew appears to flip a registry switch but it seems to be on the local pc only.


Are you aware of any USB drives that have such functionality built into their firmware?

  • 1
    As the posters below have stated; locking would either need to be hardware (like a switch on the USB) or done on the local machine. You could always mark your files as read only on the USB (right click-->Properties). Of course they could always un-mark the files from read-only and do whatever they like with them but the question is, will they?
    – emtunc
    Commented Sep 2, 2010 at 15:58
  • I've often wished my hard drive enclosure had a readonly switch like some USB flash drives do. That would make it much less unsettling to plug it into a friend's Windows machine.
    – Brian
    Commented Sep 2, 2010 at 17:40
  • Is is possible to format a pendrive using NTFS and then do it read-only with permissions? If a friend uses Linux, will the read-only protection fail?
    – kokbira
    Commented May 4, 2011 at 18:23

9 Answers 9


What about checking the "Read-only" box in the main folder's Properties and then applying to all subfolders?

  • So far this is the only solution that will work on any computer and os.
    – iKarampa
    Commented Sep 3, 2010 at 8:18
  • 10
    Note that this can be circumvented if you want to. At least on Linux (and probably on Windows) you can change the read-only state (or ignore it), if you have root/Admin on the machine the drive is connected to.
    – sleske
    Commented Apr 5, 2011 at 11:03
  • I would also add that things like Ghost or CloneDisk can trample all over this.
    – 2-bits
    Commented Jul 11, 2012 at 20:32

My best option is use DISKPART form windows


LIST DISK (To check which flash drive listed as disk in windows)

SELECT DISK 1 (It should be disk 1 if you have single hardisk attached to computer, disks naming starts from 0 but partition starts from 1)


  • Can you revert it back to write mode after this?
    – iKarampa
    Commented Mar 22, 2017 at 13:49
  • Yea, use ATTRIBUTES DISK CLEAR READONLY and it'll clear the readonly flag on the disk. Commented Mar 22, 2017 at 18:28

Any locking mechanism I'm aware of would be on your local machine.

Burn DVD's of the important stuff... :) That's about the only thing that will ensure they are read-only.

You might want to look at giving them a web interface via some apache file-sharing type of software. That would give them some sort of web-nas view and you could more easily lock down the writes...

  • 2
    1.5TB @ 8GB (dual-layer) = 192 DVDs... but they sure as hell would be read-only!
    – Nate
    Commented Sep 2, 2010 at 15:53
  • 4
    192*15min/60=48 hours to burn them. I am not doing that for any friend of mine!
    – iKarampa
    Commented Sep 2, 2010 at 16:13
  • Whoops - read that drive size wrong. I've added a web-nas idea to compensate. :)
    – Matt
    Commented Sep 2, 2010 at 17:13
  • and did not count upload time for 1.5 Tb...:) Commented Sep 2, 2010 at 21:31
  • No web server unfortunately, has to be the drive itself. Although this was an excellent suggestion!
    – iKarampa
    Commented Sep 2, 2010 at 22:27

I just finished researching this exact thing and came up with the following companies that might be relevant:

NexCopy http://www.nexcopy.com/usb-secure-flash-drives/

SecuTech (Their UniKey DRIVE) http://www.esecutech.com/software-protection/unikey-family/unikey-family.html


Addonics has a USB Read-Only portable cartridge system. simply insert your HDD 3.5" into it and it will be Read-Only (Write-Protected)



and did not count upload time for 1.5 Tb...:)

So As I understand, you want to provide your friend hole drive but your friend need part of them? Or you want to provide disk "with many important files" to your friend to get him/her access to hole 1.5 Tb content? Its a life, a lot of examples around, are you 100% guarantee your friend will be "your friend" for all entire life? Nothing personal, But just want prevent wrong steps... I do advise you to protect your info with something like that http://www.password-protect-software.com/protect-folders.html But its only my IMHO

  • It is just the accidental deletion I need protection from.
    – iKarampa
    Commented Sep 2, 2010 at 22:28
  • Ok, at this point just hide it: Free methods: makeuseof.com/tag/… Software: instantlock.net Commented Sep 4, 2010 at 9:18
  • there's no real folder-protectors. All they can be BYPASSED. The real folder-protection is an "archive" (compression:Store) and password on it. Or alternative of that... But in this case if a part of the archive is damaged ... you know...
    – Jet
    Commented Sep 11, 2013 at 19:15

Making a USB stick read only is done at the controller firmware level. From what I know, there is no USB hard drive which has the feature for read-only at the firmware/controller level. Like Jason said above, Nexcopy has the ability to make read-only USB sticks, but not USB hard drives.


This is a low-level hardware solution as opposed to a permissions-based solution.

On a Unix system, you can use hdparm to set SATA/IDE device parameters. One of those parameters is a read-only value.

Here is an example assuming your device is scsi device b (sdb):

Turn on read-only value (CAREFUL!)

hdparm -r1 /dev/sdb

Turn off read-only value

hdparm -r0 /dev/sdb

Read the current value

hdparm -r /dev/sdb

from man hdparm

-r Get/set device readonly flag (DANGEROUS to set)

-R Get/set device write-read-verify flag

  • 1
    Can this solution be reversed?
    – DanRan
    Commented Dec 13, 2020 at 3:34

I think that you cannot ensure that your data will be only read, when you have to give disk to someone.

I'd advise you to make backup of your files, so that if something happens to data on your drive you'll always have a copy.

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