If you are willing to make a few tweaks to your registry, you can get Windows 8.1 update 1 right now. By adding a value to your registry, this will give you access to download and will get you the bits right now, without accessing any third-party.

Several users have reported that the method is working and have successfully downloaded the update. The current thought is that by tweaking the registry, it mimics your machine to be that of a user who is dogfooding the update and then sends the bits to your machine.

In regedit, navigate to “HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\” and create a new key called “SHWindowsPoolS14″, now reboot your PC and check for new updates. You should see “Update for Windows 8.1 for x64-based Systems (KB2919442) – (S14 Prerequisite v01.0008)“, this is the first in a series of updates that will update your PC to Windows 8.1.1 (or whatever it’s called).

We wouldn't be surprise if Microsoft blocks this workaround very quickly and surely did not expect this way of obtaining Windows 8.1 update 1 to make it out into the wild in this way.

As with any leak or workaround like this, proceed with caution as you can bork your Windows install.

Update: Microsoft has plugged the registry tweak and removed the files from the known Microsoft server locations, but you can find the bits on MDL forums or just look through our comments. Again we warn you that downloading files from non verified locations is not recommended..

The Updates must be installed in the following order:

KB2919442 KB2939087 KB2919355 KB2932046 KB2938439 KB2937592

And finally, if you have the Feature Pack/Update 1 installed, you can enable Enterprise mode in Internet Explorer (also for Windows 7) by doing the following steps:

Ensure you have the correct version installed:

Enterprise mode can be enabled using two Group Policies (in a corporate environment system admins would do this for their employees). Hit Windows + R and type ‘gpedit.msc’ in the Run window. In the Group policy editor, browse to Computer Configuration > Administrative Templates > Windows Components > Internet Explorer, there you’ll find, among others, these two policies: “Let users turn on and use Enterprise Mode” and “Use the Enterprise Mode IE website list”.

Source: Bav0 & MDL