OS: Windows 8.1
Issue: Windows 8.1 not showing on MS Store.
1. Make sure that the GDR update is installed KB2871389
2. Make sure that you are not using a Volume License, Enterprise Edition of Windows 8, or a Preview version of Windows 8/8.1
3. Run WSRESET.exe from a command line.
1. Press the Windows key on the keyboard and press "S"
2. Type "CMD". Right click on it and click on "run as administrator"
3. Type "WSRESET.exe"
4. Sync you App License:
1. On the Start screen, tap or click Store to open the Windows Store.
2. Swipe in from the right edge of the screen, and then tap Settings.
3. (If you're using a mouse, point to the lower-right corner of the screen, move the mouse pointer up, and then click Settings.)
4. Tap or click App updates.
5. Tap or click Sync licenses.
5. Make sure that the following services and running:
1. Press the Windows key on the keyboard and press R
2. type "services.msc"
3. Make sure that the BITS, Windows update, and Cryptographic Services are all started and set to automatic. If not, right click on the service and click properties. Set the startup type to Automatic, and click start so the service status will say started.
5. Open Internet Explorer, and type the following in the address bar
If this process won't work, then proceed to the steps below;
1. Open MS Store App
2. On MS Store App – Open Charms Bar
3. Go to Settings – Choose App Updates
4. Click Sync Licenses.
5. Click Start – Type “WSRESET” – Run as Administrator
The Windows 8.1 Upgrade Option should appear now.