error code 0xc03f300d

I actually love this mess up, for two reasons:

1. It is a perfect example of why the standard reply a lot of people get to reboot/reset/reinstall is a dangerous or pointless and lazy at best, advice
2. It is a perfect example of why a world of always online software will/would be bad for end users

Good luck to all of us, the future promises to be interesting...

What's not clear is the 'switch' that's been flicked to create the situation.  From all the posts it can only be something in the Store or account management and not local issues.  Don't see that an update from Windows, Defender or something similar would affect so many different devices albeit with the same OS.  Perhaps we should all just get onto Windows support and give them the same story.  Three rebuilds here, resets of Store Cache, Disk Cleanup, new accounts on the same PC created as admins to download and all hit the same problem which is 'no you can't do it'

If we or Microsoft can identify the switch made then a solution is possible

Same issue here and I thought that I was losing my mind on this friend's 8.1 tablet .. good to see I'm not alone, I just wish I hadn't rebuilt the damn thing twice already! =)

PS:  Perhaps this whole thread should be copied into the Windows 10 forum - they might listen then

It seems very clear that the thrust of Microsoft's efforts is to move the market along to Windows 10.  This is right from their perspective as they want us to use the latest incarnation of the operating system.  If they were a car manufacturer and we were griping about getting parts for an old model they are not going to be too interested.  That being said, Microsoft GET YOUR ACT TOGETHER!  you are alienating a large number of paying customers who, in the modern world, can find other devices but who would rather keep with the apps, look and feel, ways of working and comfort factors.  Remember that we are loyal at the moment.  FIX IT PLEASE