Since last Thursday, it is possible the Windows 8.1 Update to download if you have a device with Windows 8 or Windows RT. For users with Windows RT, however, it is temporarily not possible to update.
Microsoft today released the Windows RT 8.1 update, the update that is specifically made available for tablets with Windows RT software, taken offline. The update is not to be found in the Windows Store. The reason is that the update would ensure that the tablet would be unusable. Among a limited group of users for such large problems As indicated in the following statement, the problems currently being investigated by Microsoft.
Microsoft is investigating a situation Affecting a limited number of users updating Their Windows RT devices to Windows RT 8.1. As a result, we have Temporarily removed the Windows RT 8.1 update from the Windows Store. We are working to resolve the situation as quickly as possible and apologize for any inconvenience. We willprovide updates as they become available.
The responses to the Microsoft forums we can get that the problem has to do with a bluescreen that appears after restarting the tablet to install the update. Indicating that the Boot Configuration ‘file is missing. Appears on this screen If you get this message also you can find a solution that seems to work for many people.