Just a few hours back, Microsoft released Windows 8.1 Preview build (build number 9341) to the public at BUILD 2013 conference in San Francisco. While both 32-bit and 64-bit Windows 8.1 Preview ISOs are available to perform a clean install of Windows 8.1, existing Windows 8 users can update to Windows 8.1 with a few mouse clicks.

Despite a warning from Microsoft that users who upgrade Windows 8 to Windows 8.1 Preview will need to reinstall all apps installed from the Store and also desktop programs when upgrading the Preview to the RTM build, many users are upgrading their existing Windows 8 installations to Windows 8.

Upgrading Windows 8 to Windows 8.1 is relatively simple: download the update file, run it, restart your PC when prompted to do so, click the notification on the Start that appears after the reboot to visit Windows 8.1 update page on the Store, and finally click the Download button to begin downloading Windows 8.1 update and then automatically install the update on your PC.

Unfortunately, many users who’re trying to upgrade to Windows 8.1 by installing the update are experiencing some issues. It seems “The update is not applicable to your computer” is a common error. The error appears when you try to run the standalone update downloaded from the Preview site.

According to Microsoft, the error appears if the base language (the language that you selected during Windows 8 setup) is different than Windows 8.1 Preview supported languages. That is, Windows 8.1 Preview update is compatible with English (US), Chinese, French, Japanese, Arabic, Russian, Turkish, Swedish, Spanish, German, Portuguese (Brazil), and Korean languages.

Even though it’s possible to easily change the base language, Microsoft suggests against it. According to Microsoft, if you upgrade to Windows 8.1 Preview after changing the base language, it will permanently change the language as Windows creates a new system restore image based on your 8.1 base language during install.

If the base language of your Windows 8 is not supported, you can download Windows 8 ISO file and then install it without any issues. The error will also occur if you’re trying to upgrade Windows 8 Enterprise edition to Windows 8.1 Preview.

How to fix “The update is not applicable to your computer” error

Step 1: Download the update file by visiting this page and then clicking Get update button. If you have already downloaded, skip this step.

Step 2: Place the downloaded update file (.MSU file) in the root of your Windows 8 drive (generally, it’s “C”) and rename it as preview.msu (please don’t change the extension). Next, create a folder named 8preview in the root of Windows 8 drive. For instance, if your Windows 8 drive is “C” then, the 8preview folder path would be C:\8preview.

Step 3: Open Command Prompt with admin rights. To do this you can either follow our how to run a program as admin in Windows 8 guide or press Windows + X keys to see a small menu with Command Prompt (admin) option.

Step 4: In the prompt, type the following command and press enter key.

Expand –F:* c:\preview.msu C:\8preview\

Replace “C” with your Windows 8 drive letter.

Step 5: Next, type the following command:

DISM.exe /Online /Add-Package /PackagePath:c:\8preview\Windows8-RT-KB2849636-x64.cab

In the above command, replace x64 with x86 if you’re running x86 version of Windows 8.

Once DISM completes its job, you’ll see “Restart Windows to complete this operation?” message. Press “Y” key to restart.

After restarting your PC, “Get Windows 8.1 Preview for free” notification will appear on your Start screen(might take up to a minute). The text will not appear correctly in the Windows Store when you visit to download the update but it will smoothly upgrade your Windows 8 to Windows 8.1. From here on, you can follow our how to upgrade to Windows 8.1 guide for step-by-step instructions.

Thanks to John at MSFT forum for the fix.