Install Parallels Tools in a legacy Windows virtual machine

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Upon installing Parallels Tools in Windows Vista-Windows 8.1, the Allow permanently switching Windows to Test Mode to update Parallels Tools prompt has popped up.

What does it mean and what steps are required to be performed?


Among other things, Parallels Tools include a number of drivers that need to be installed in a virtual machine.

And in order for these Windows drivers to be installed, they need to be signed with valid cross-certificates. Due to some changes in Microsoft driver signing policies, the certificates required to sign drivers for Windows Vista - Windows 8.1 are expired and cannot be renewed. As a result, the drivers signed without the respective cross-certificates are considered unsigned by the operating system and cannot be loaded by Windows Vista - Windows 8.1 in normal mode. To install Parallels Tools and ensure the smooth work of the Windows OS in Parallels Desktop for Mac, it's required to switch Windows to Test Mode

If Test Mode is enabled, the system will allow installing drivers signed using test certificates. Normally test certificates are only used during development and testing, but due to aforementioned changes it is now the only way to install Parallels Tools in Windows Vista/7/8/8.1 virtual machines.

To install Parallels Tools in such a virtual machine, follow the steps below:

  1. When presented with the prompt to switch to test mode, click Allow.
  2. Then the confirmation dialogue will appear. Check I understand the risks and allow enabling Test Mode and click Allow and Restart.
  3. Upon clicking the last option, Test Mode will be enabled and Windows will restart. After the restart, Parallels Tools installation will be initiated automatically.

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