I originally installed Windows 8 Pro using an EN-US ISO or selected US as the install language and then later changed the default language to EN-GB or something along those lines. Anyway when I used the upgrade windows with just a Product Key(windows.microsoft.com/en-us/windows-8/upgrade-product-key-only) hack to get the 8.1 ISO, the installer obviously detected I had the EN-GB language pack installed as the default and sent me the EN-GB 8.1 ISO with only the EN-GB language pack. All fine but then when I came to install as an upgrade I only had 2 options - keep nothing or keep my personal files - keep my Apps selection was missing. When I tried to boot off the ISO and upgrade, there was a compatibility error if I tried to select the keep all files and apps. So long story short the dimwits at windows, as we know, have all kind of sneaky little tricks to mangle your sanity. You can't upgrade and keep your apps if the language pack on the 8.1 ISO does not match the originally installed language pack. There luckily is a fix, which damn near drove me crazy trying to find!! I found a few people having my same problem but no fix - they just downloaded the ISO all over again with the correct localization but I didn't have any more data to download so I hunted for the answer. On the computer you are trying to upgrade you need to change the installed language in the registry to match the localization of the 8.1 ISO you are trying to use to upgrade and change all the location and language/pack & settings on the computer to match the localization of the 8.1 ISO. The example below is to change from EN-GB to EN-US, you will need to substitute the localizations that match your situation. You can use Google to find the install language code that matches the localization you need, or maybe someone can find them and post them here. Fix found here, was originally used by people with with EN-GB localization to enable them to install the 8.1 Preview that was locked to EN-US localization: pcadvisor.co.uk/how-to/windows/3455141/how-upgrade-windows-81-uk/ - Go to the Control Panel and click on Clock, Language and Region. - Click Region, then the Location tab, and change Home location to United States. - Click on the Administrative tab, then Change system locale... and set it to English (United States). Reboot if prompted. - Install the US language pack by typing Language on the Start screen and clicking Settings on the right. Click Lanugage in the list of results. Double-click on the Engligh (United States) entry and click the link: Download and install language pack. - Ensure you set this as the primary language once installed (which can take half an hour). Restart if prompted. - From the Start Screen, type regedit.exe and hit Enter. This will launch the Registry editor. - Go to this key, by navigating through the tree, starting with HKEY_LOCAL_MACHINE: HKLM\System\CurrentControlSet\Control\NIs\Language - Scroll down to the bottom of the list and find InstallLanguage. Double-click and change the value from 0809 to 0409. - Close regedit and reboot your machine. Restart the upgrade and the keep apps option should be there What a pleasure!!!! Before I found the fix above I also changed 2 other things in the sources folder of the 8.1 ISO, neither of which helped so I don't think they are necessary but here they are anyway. Changed the ei.cfg to this: [EditionID] Professional [Channel] Retail [VL] 0 Changed the cversion.ini to the version of my Windows 8 build: [HostBuild] MinClient=9200.0 MinServer=9200.0 None of the links above are active because I'm a n00b and only got 0 posts One thing to note is your localization will be matched to the 8.1 ISO after the upgrade is finished. But you can install the language packs you need and change the localization once the upgrade is complete.