Trick Lets Windows 7 to Run 120 Days for Free

In order for Microsoft to verify legitimate versions of Windows 7, users must activate their copies of the operating system within a finite time limit. On first inspection, that time limit appears to be 30 days, but as was the case with Windows Vista, there is a way to stretch that limit to nearly four months.

Like Windows Vista, the upcoming Windows 7 comes with a command line utility called the Software License Manager (slmgr.exe) that allows the user to issue "-rearm" switch that will reset the countdown timer back to 30 days. This command may be issued a maximum of three times. If a user issues this command at the end of each 30-day period for three times, he or she would be able to use Windows 7 unrestricted for up to 120 days.

The procedure to reset the countdown is identical to the process used for Windows Vista:

  1. Start the command line by clicking Start > All Programs > Accessories > Command Prompt (Run As Administrator) – or for a shortcut, hit the Windows Key + R and type "cmd".
  2. At the command line, enter in "slmgr –rearm" without the quotations.
  3. Restart Windows 7.

After the reboot, your counter will have reset back the 30 days.

Microsoft confirmed to Computerworld that this trick does indeed work. "This means [that] a total of 120 days total time is available as a grace period to customers that take advantage of -rearm," said a company spokeswoman.

Interestingly enough, the Microsoft representative said that extending the activation grace period using the slmgr is not a violation of the EULA.

This could be the perfect way to install and run your RTM disc of Windows 7 right now and stave off activation until you receive your licensed product key on October 22. Be careful to only install the edition that you intend to purchase, which could involve modifying the disc image. (Read more about this procedure at Windows Secrets.)

Of course, if you run this rearm process before your 30 days are up, you'll get fewer than your 120 days maximum. It'll be best to mark it on your calendar and set a reminder.

Marcus Yam
Marcus Yam served as Tom's Hardware News Director during 2008-2014. He entered tech media in the late 90s and fondly remembers the days when an overclocked Celeron 300A and Voodoo2 SLI comprised a gaming rig with the ultimate street cred.
  • tsiberious
    Heck, I wipe my os about 2 times a year anyway. This might have been a mistake for them :)
  • zerapio
    Wow, I reinstall once every 3 or 4. I'm in my 3rd year on my current rig and it still runs great.
  • apache_lives
    Old News THG
  • daship
    If you wipe that much you need to learn a little bit about a computer.
  • bertschkid
    I used to wipe about 4 times a year just because I like the feeling of a fresh windows install. However, now I use my computer a lot for business and I haven't reinstalled windows since I got Vista in August of last year.

    However, I will probably get Windows 7 so will wipe everything in October.
  • nachowarrior
    dashipIf you wipe that much you need to learn a little bit about a computer.if you're running x64 with a lot of 32 bit programs it tends to fragment the crap out of your hdd. So W&RL is required. Try all the defrag programs you want, try as you might they still don't work nearly as well as a fresh install. win xp x64 you're looking at 27% or more fragmentation after defrag. A fresh install is also great because you can install all of the latest and greatest dri\/ers without worrying weather they were remo\/ed properly or not. Just makes sense on a windows machine. Linux kernels howe\/er are a different story.

    I generally do 6 months or so anyway, keep all my install files updated and on a separate hdd. Works out fine for me.
  • Boxa786
    Awesome, so they are telling us, and the general public how to avoid activation.

    Sounds like a great way to bring in more consumers to use legit copies. Use this for 4 months then wipe your HD and start this all over again.
  • Sicundercover
    People Rearming has been around since XP; this is nothing new.
  • Meh, I reinstall more than once a month anyway so whatever.

    No, I don't have to do that but keeping a minimal OS-install means it's the most efficient way to keep a clean install for half an hour's worth of work.
  • nitto555rchallenger
    Boxa786Awesome, so they are telling us, and the general public how to avoid activation.Sounds like a great way to bring in more consumers to use legit copies. Use this for 4 months then wipe your HD and start this all over again.No, after March 1, 2010 all PC's with Windows 7 RC installed will begin to automatically shutdowns every 2 hours whether its user instructed or not. This will happen till June 1 2010, when it will fully expire, so its best to either move on to Windows 7 or downgrade to Vista or XP before this time, because you'll be locked out completely. I say move on to 7 or go back to XP.