As with the release of any new operating system, some users have experienced problems installing and running Windows 8.1 and Windows RT 8.1.
On this page we'll report the most serious bugs or upgrade problems and offer potential solutions. Help us and fellow readers identify and fix other problems using the comments facility at the foot of the article.
Windows RT 8.1 BSOD
The most serious bug reported so far affects Windows RT 8.1, with some users experiencing the dreaded Blue Screen of Death or Boot Configuration Data File errors after installation.
The problem is so severe that Microsoft has decided to pull the Windows RT 8.1 update from the Windows Store.
Many users have been unable to repair devices affected by the Windows RT 8.1 update, so Microsoft has released a Surface RT recovery image to help restore tablets to working order. Beware that clicking on that link will immediately instigate the 3.6GB download.
It's not yet clear when Microsoft will release a patched version of the update.
Windows 8.1 installation snags on drivers
The upgrade installation of Windows 8.1 stalled on one of our office machines because of a driver issue. Windows demanded that we uninstall "Sentinel Runtime Drivers" before the installation could proceed, but there was no obvious means of removing them via the Add/Remove Programs facility.
We found that following the instructions published by SuperUser.com solved the problem.
Remember that if you're copying the address of the downloaded file into the Command Prompt, you can't use the normal cut and paste keyboard shortcuts. Instead, use the Paste facility in the dropdown File menu of the Command Prompt.
SkyDrive files available "online only"
If you'd synchronised desktop files on your PC with SkyDrive before installing the 8.1 update, you may have been shocked when you first looked into your SkyDrive folder to discover folders now marked as available "online only".
On our test office PC, this label proved misleading. Files stored inside folders that were ostensibly "online only" were still available even when we disconnected from the internet, and the local file storage afforded to SkyDrive suggests those files are indeed still saved locally.
Microsoft's support site claims that: "The SkyDrive files you've saved or previously opened on your PC are automatically available offline on that PC. Any files you create on SkyDrive.com or another computer are online-only to save space on your PC."
To avoid any confusion, open Windows Explorer, right click on "SkyDrive" in the left-hand pane and click "Make available offline". All your files should now be synchronised locally, if they weren't already.
Limited upgrade path from Windows 8.1 Preview
This issue is not a bug: it's a pre-announced problem for those who jumped early and installed the Windows 8.1 Preview on their PC. Although you can upgrade in-place from the Preview to the final code, you may have to reinstall all your desktop and Windows Store apps.
Unofficially, our very own Darien Graham-Smith has written a blog post explaining how you can upgrade in-place from the Windows 8.1 Preview to final code and keep all your data, settings and programs intact. Several readers have reported on the comments below the blog that the method has worked for them, but we offer no guarantees, nor technical support if it goes wrong.