Windows 10 Developer Trial

If you want to use Windows 10 to develop software or to try software you can download a trial version from here.

If you need re-arm (extend) your trial period for development purposes you can use this command in the command line.

slmgr.vbs -rearm

How to shrink or compact VirtualBox .vdi images

This works for Windows 


You have to do the following steps:

  1. run defrag in the guest (Windows)
  2. nullify free space:

    With Linux guest run this:

    sudo dd if=/dev/zero of=/bigemptyfile bs=4096k sudo rm -rf /bigemptyfile 

    With Windows guest, download SysinternalsSuite and run this:

    sdelete –z 
  3. shutdown the guest VM

  4. now run VBoxManage’s compact command

    VBoxManage.exe modifyhd thedisk.vdi --compact 

This reduces the size.


This works for Mac OS X

Open Terminal

Enter the following command:


VBoxManage modifyhd -compact “/Users/user1/VirtualBox VMs/Windows 7/Windows 7.vdi”