Extend the Vista activation period

Martin Brinkmann
Feb 3, 2007
Updated • May 29, 2013

Did you know that it is possible to extend the 30 day evaluation period of Windows Vista to a maximum of 120 days with a single command from the command line? You can use the following command to reset the counter up to three times to use Vista for a period of up to 120 days without activating it.

Open the command line in the following way: Use Windows-R to open the run box of your system, type cmd, and hit the enter key on the keyboard afterwards.

Use the -rearm option of the file Slmgr.vbs to prolong the activation period,. The command that you need to use for that is: Slmgr.vbs -rearm; This if of course not the real deal (full actication) but can be helpful if you have no time to activate Vista in the first 30 days or want to test it for an extended period of time.

You can run the command for a total of three times before you can't extend the activation period further. It is however possible, with a little bit of Registry tweaking, to cheat the operating system so that you can run the command again.

Please note that you may need administrative privileges to run the command on the command line, especially if you are using Windows 7 and not Vista. The command should work just as well under Windows 7 as it did under Vista, so that you can extend the trial phase by 90 days for a total of 120 days before the operating system needs to be activated.

Instead of using Slmgr.vbs -rearm on the command line, you can also run the following commands with the same effect: 

  • sysprep /generalize
  • slmgr /rearm
  • rundll32 slc.dll,SLReArmWindows

Keep in mind that rearm is only working three times. If you want to get the maximum number of days you need to run it when the 30 day countdown is almost over, but before it has expired. This way, you can test the system for four months before you need to enter a valid product key to continue using it.


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  1. R said on February 23, 2007 at 11:52 am

    You can only did this 3 times before it locks you out.

    First 30 days + 30 + 30 + 30 = 120

  2. Hornswaggled said on February 4, 2007 at 1:34 am

    Okay Im an idiot, sorry for the above comment. Thats only good if you purchased xp in the past 3-4 months (I had to for work). I should of mentioned that before.

  3. xFilthyxJesusx said on February 4, 2007 at 12:37 am

    I thought you could use this to extend Vista for basically ever.

  4. Hornswaggled said on February 3, 2007 at 10:57 pm

    Just came across these sites:

    and vlite.net seems to be a cool tool before installing it.

    Seems like there is no need to actually purchase Vista if I am reading this stuff correctly.

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