How to rearm Windows trial license

This post is meant for testers who use to run cross browser tests. If you are a tester and do not know about, I recommend reading our post on cross browser testing tools. was created by Microsoft and allows you to use Windows virtual machines without purchasing Windows licenses. Its awesome! The downside is that the virtual machines use evaluation versions of Microsoft Windows and are therefore the license expires. Starting Windows Vista, Microsoft lets you extend your grace period through a process known as ‘rearming’. You typically get up to 3 rearms or 4 times the trial period!! In this post, we will show you how to rearm a Windows 7 virtual machine that we downloaded from

Oh noes! My trial Windows license expired. Here is the initial snapshot (windows license expired) to begin with.


Never fear, I can extend the trial period by running the following command from an administrative command prompt.

*slmgr -rearm

We need to reboot the system for the changes to take effect.

Now to check the current license, time remaining, rearm count use the command
* slmgr -dlv


You can use the following command from administrative command prompt for activation
* slmgr -ato


There you go..rearmed for action!!

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