The kernel-mode code signing policy for 64-bit versions of Windows Vista and later versions of Windows specifies that a kernel-mode driver must be signed for the driver to load. So unsigned drivers like the one (AVR Jungo USB Driver) I was trying to install doesn’t seem to work right away on windows 8. In case if you are interested in what driver signing means please take a look into this article.

The steps to install a unsigned driver on windows 8 is as follows.

  1. From windows 8 control panel choose General –> Under “Advanced Startup” –> Restart now.

Now the system will restart and might take some minutes to show up the boot menu. Wait for It patiently.

After some time you will be prompted with a menu with following options.

  1. Continue

  2. Troubleshoot

  3. Turn off

Choose Troubleshoot

Then the following menu appears.

Refresh your PC
Reset your PC
Advanced Options
Choose Advanced Options

Then the following menu appears

System Restore
System Image Recovery
Automatic Repair
Command Prompt
Windows Startup settings
Choose Windows Startup Settings, then Click Restart.

Now the computer will restart and the boot menu appears. Choose “Disable Driver signature Enforcement” from the menu. Now windows will start and you can do the installation of the driver that is not signed. Smile

I did this specifically to install the AVR Jungo USB Driver which is a 3rd Party driver required by the product am developing and ended up successful. Hope this helps.