Microsoft has temporarily pulled Windows 8.1 for Windows RT tablets from its servers, following a launch to the masses on Thursday. The Windows 8.1 version for all other devices not on the RT platform is still available for download from the Windows Store.

The Redmond-based company has pulled the sizable update because of issues affecting "a limited number of users updating their Windows RT devices to Windows RT 8". Microsoft says it is working to resolve the situation and will keep us updated.

The problem lay within the start-up screen during the process of upgrading Windows RT 8.1. Many users have seen a blue screen saying, "Boot Configuration File is missing some required information". WP Central reports the problem can be fixed by creating a bootable USB drive from a Windows 8 device. It's not too technical a process.

Apart from issues with Windows RT, the Windows 8.1 upgrade process has been relatively smooth for users. The only real issue has been download times, presumably because Microsoft didn't anticipate as much download activity from its servers.

Windows 8.1 was released on Thursday with a number fixes for the Windows 8 problems. As well as bringing back the Start button, Windows 8.1 adds better multitasking, revamps to core apps, unified Bing search, and more. The update is available free, which definitely makes the situation a bummer for Windows RT users who haven't yet updated. We'll be tracking the situation.