Symptoms

If you cannot start your Parallels virtual machines when working with Parallels virtualization products for Windows (Parallels Desktop for Windows, Parallels Workstation Extreme, and others) and get this message: "Unable to start the virtual machine due to software incompatibility.", this may be caused by programs installed on your Windows-based host computer.

These programs may conflict with Parallels virtualization products for Windows and prevent you from starting virtual machines:

• ESET NOD32 v2.x
• Internet Download Manager (Tonec Inc.)
• Aventail VPN Client
• EMBASSY Trust Suite
• AT&T Communication Manager
• PC Tools Firewall Plus 7.x

Resolution

If you have one (or all) of the aforementioned programs installed on the host computer, do one of the following to solve the problem:

• Try to update the program(s). For example, ESET NOD32 3.x does not conflict with Parallels virtualization products for Windows.
• Remove the program(s) from the host computer.

The problem is connected with Windows network subsystem. That is why, if you experience this problem, but no programs mentioned above are installed on the host computer, pay special attention to the software that may cause changes in the Windows network subsystem.

If you find a program that causes such difficulties and is not listed here, please contact the Parallels support team.