The VHD we have for download from www.microsoft.com/ilm2 has a timeout issue. It is Windows Server that needs to be re armed to get another 60 days of evaluation.
If you log into Windows after the Activate Later button is activated you can run the following command from Start-Run and then restart to get another 60 days.
Product Manager - ILM
ps I am intending to build a new image and to replace this one but it is a couple of weeks late so will be available around 15 Feb.