Windows 7 RC users may face tricky route back to Vista

The unprecedented number of PC users who installed Windows 7 release candidate (RC) will soon have to decide whether to upgrade to the new OS or face bi-hourly shutdowns and significant hassle re-installing their old version.

Beginning on February 15, users of machines running the RC will see an expiration message above the taskbar, followed on 1 March by the start of shutdowns every two hours. The next key date will be June 1, the point at which the entire desktop wallpaper will be replaced with the message "This copy of Windows is not genuine", a state that will disable updates of any kind and the ability to use Microsoft applications.

"To avoid any data loss, I suggest making plans to move to a released version of Windows 7 before the automatic shutdowns start. During these shutdowns, your work will not be saved," says Microsoft's Brandon LeBlanc in a blog reminding the world of the issue.

At this point RC users have only two options if they want to continue using their computers; to upgrade to Windows 7 through a full install, or revert to a previous operating system such as Vista. How easy that the latter choice proves will depend on the way the OS was installed, the size of the hard disk, and the technical expertise and patience of the user.

Anyone who installed the RC over Vista or XP should be able to return to that version as long as their PC contains the folder Windows.old and the available hard disk space is double that consumed by this folder.

However, as an article on the topic makes clear, even then the re-install of Vista or XP could turn into a time-consuming process unless the user is willing to start from scratch and has the required OS disks to hand.

The message from Microsoft is clear: let go of the past and pay to upgrade to Windows 7.