Predator: use your USB/flash drive to lock your computer when you are away

Whenever I walk away from my computer I make it a habit to hit specific shortcuts on my keyboard to sleep my computer while I am not using it (so it is locked whenever someone tries to wake it up and use it). I do this because I do not want people accessing my computer while I am away. Predator…



…is a program which allows you to do something similar (i.e. lock your computer) when you are AFK (away from keyboard) but in a different manner. Instead of you having to tell Windows to sleep your computer before you go away (either via hotkeys or the start menu), if you use Predator you simply have to unplug your USB/flash drive and your computer will be locked. The only way to “unlock” your computer is to either plug in the USB/flash drive you setup to work with Predator or to enter the password you set in Predator (the password is a fail-safe for people who may lose their USB/flash drives).

Predator works in a fairly simple way. You install Predator on your computer (note you are installing on your computer and not your USB/flash drive) and create a “key file” (“Create Key”) on the USB/flash drive you want to use to lock/unlock your computer (besides creating a “key file” on your USB/flash drive, Predator does not alter the contents of your drive in any other way). Then whenever you unplug the USB/flash drive, Predator will lock your keyboard (no Alt + Ctrl + Del to kill Predator) and mouse, and darken your computer screen. When you reinsert your USB/flash drive, the keyboard and mouse are unlocked and your computer screen is restored to normal.

As an added security feature, if someone is ever able to grab a copy of the “key file” stored on your USB/flash drive, they will be unable to use it to access your computer because Predator constantly changes the “key file” on your USB/flash drive every 6 seconds.

From Predator options, you can change a few settings to customize your usage with Predator such as the time (in seconds) it takes for Predator to lock your computer after you remove your USB (see “Interval”) and how dark you want the screen to be (see “Screen Darkness”). Other handy options include “Fast Detection” which makes it so Predator locks your computer instantly when the USB/flash drive is removed regardless of what “Interval” is set to, the ability to start Predator automatically on Windows boot (since Predator is based on your PC instead of on your USB/flash drive, you must have Predator running on your computer in order to be able to lock your computer so it is a good idea to allow it to run automatically at Windows boot), and multiple monitor support.

Lastly, with Predator you may use one single USB/flash drive for multiple computers. To do this you will need to install Predator on each of the computers and create a “key file” for each computer on the USB.

One cool thing I noticed with Predator is if you set Predator to run at Windows boot, if someone manages to restart your computer while it is locked with Predator (they would need to do a hard reset), Predator will lock your computer upon reboot because it instantly looks for the USB/flash drive whenever it is turned on.

Two words of caution:

  • I noticed if you use your password to unlock your computer when it is locked by Predator instead of inserting your USB/flash drive, and then you insert your USB/flash drive, you must manually right click on the Predator system tray icon and select “Resume monitoring” to tell Predator to start working again (Predator is not able to detect if you plug in your USB/flash drive when monitoring is disable… obviously =P).
  • Do not unplug your USB/flash drive when the Predator system tray icon is red. When it is red it means Predator is changing your “key file” and if you unplug it at that time, you may have problems unlocking your computer with your USB/flash drive later.

Of course for people who put a password for their Windows login and make it a habit to lock/sleep their computers when they walk away, Predator will not be very useful. However Predator is very useful for people who are habitual USB/flash drive users.

You may download Predator from the following link:

Version reviewed: 1.1.1

Supported OS: Windows 2000/XP/Vista/Win 7

Limitations: Predator is free for home use only

Click here to download Predator

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  • septib

    hi ..i lost my password but i have the usb flash drive …how can i recover my password? … help me please

  • Sam

    Predator – only screen locker..if you want to protect your Windows login use Rohos Logon Key
    Program Rohos Logon Key use a single USB Key to log into your Home, laptop and office computer

  • i want to computer key because not downlond plz help me

  • navneet kumar

    hiiiiiii its navneet ..i want to know about preador…sir..after creation of password with the help of usb…..and….if i lost my usb flash drive…then what can i do…any sujjestion and reply soon…

  • Alan Macbay

    if predator locks the keyboard without USB key, how can u type the password in manually if u lost ur usb key?

  • supernoop

    Sorry, my English is not good. Will this software lock the computer after booting? (I mean, someone start up my computer -> get to Windows -> lock?).

  • stupidfool

    hi guys,

    i think i got some problem. Actually i just download this program and it worked fine but lol i was replacing old passwords with new ones and now i have the key but i forget my password. I can unlock my computer with usb but can’t remember my password.
    Any help pls? yea i have tried looking in log there are just wrong passwords not the working one.


  • Ashraf

    @Tortuga: To answer your first question, when creating a “key file” you need to specify which USB you are want to create the “key file” on by selecting the “drive letter”. Look at “Create key on drive” at the bottom in my above screenshot.

    For your second question: yes you can unlock via password. You see the purpose of Predator is to make it easier to lock/unlock your computer if you are one of those people who make it a habit to use a USB drive when you are on the computer. So even though you can unlock via password, for many people it is faster to just plug in their USB to unlock. As I said earlier, it is just a matter of preference.

  • Tortuga

    Hello All

    Maybe {well, I’m sure!!} I’m missing something … ;)

    1• What happens if one has several externals (3x) & kees (2x) plugged at the same time, permanently? [Actually I use them as ‘extensions’ of my internal (only 320G), so I now have 1T available]
    Some of them do travel from PC«to»Notebook, depending on the needs. So, each time we unplug any of them, the machine is locked??
    Or does one need to designate a specific USB Key for Predator? If so, we can’t use it for anything else (backup or transport), right?
    I’m confused :(

    2• USB Keys nowadays are inexpensive but also quite cheap and therefore the lifespan is unpredictable. If it ‘dies’ suddenly, what happens? Are we locked out permanently?


    EDIT: Ok, re-read the article & think I answered my question #2. One can unlock via Pwrd w/out the USB, right? Hummm, in that case why do we need the USB at all?

  • Ashraf

    @Harlan: Great suggestion.

    @Mike: True, I agree it may be somewhat of a gadget mania. I myself have no need for Predator because I don’t carry around USBs.

  • Mike

    @Ashraf– Yep, I get that it’s personal preference. But I think it also may be gadget-mania. Is it really easier to pull a USB drive out of a computer than simply clicking a screensaver/lock icon on the screen? Or is it just one more thing to lose? And as to a reboot, if you’re sensitive about your computer, shouldn’t one be using a logon password? I just don’t get the need for extra complication. But perhaps some want a new gadget to carry along.

  • Harlan

    For better security, encrypt your entire hard drive or entire partitions using TrueCrypt. Combined with a password-protected screensaver which activates quickly, or manual system locking, you can rely on your data staying secure. Predator is a nice idea, but I agree that it is another potential source of problems in using Windows. Tying up a USB port and a USB drive also seems wasteful to me.

  • Ashraf

    @david roper: I am experimenting with a few things.

    @Mike: Well for some people it is a lot easier to plug in/out their USB. It really is a matter of preference.

    Furthermore, Predator is a bit more secure because with a screensaver if you do a hard reset and restart the computer, the person will have access where as if Predator is running, even after reboot it will lock.

    @Kite: You can create a USB backup using USB Image Tool and you can always unlock your computer via the password you setup in Predator:

    The only way to “unlock” your computer is to either plug in the USB/flash drive you setup to work with Predator or to enter the password you set in Predator (the password is a fail-safe for people who may lose their USB/flash drives).

  • Kite

    Nice idea until you realise that USB Drives are quite fragile – there is no option for a backup copy, or alternative way to unlock the computer.

  • Mike

    I just don’t get Predator–it simply adds a further complication, a USB drive, to the simple act of locking one’s computer. Isn’t just putting and using a locking screensaver shortcut on one’s desktop or Quicklauch bar simpler?

  • david roper

    I want to rate the article 5 stars. Were is the rating bar?
    Oh well. They all get 5 stars from me.

    That’s two…!!