cannot project to a tv hooked up by hdmi. Could with windows 8 but not 8.1

Hi,

Did you use Project 2010 to print a plan to TV?

I find the same issue in Windows 8.1 Preview: FAQ.

Windows 8.1 Preview and Windows RT 8.1 Preview should work with the same devices and programs that work with Windows 8 and Windows RT. In some cases, the device or program might not work or may require an update, or you might need to uninstall some programs, and then reinstall them after installing Windows 8.1 Preview.

It suggests that reinstall, we may test to check the issue.

For more detail information, please refer to the following link:

http://windows.microsoft.com/en-in/windows-8/preview-faq

Regards,

George Zhao
TechNet Community Support