For Lenovo users - I found this on their company website regarding 8.1 updates. You will see there are a number of models which they are recommending not to upgrade. Counting all the models I assume, just here, there are hundreds if not thousands of Lenovo laptop users who have been affected. And so we wait for at least an acknowledgement...
Notes:
- Ideapad can only support the current preloaded hardware and software configuration. Therefore, depending on a specific configuration, it might not be recommended to upgrade your computer. That is because some hardware issues cannot be resolved currently.
- It is not recommended to upgrade the following models to Windows® 8.1 because some VGA related issues cannot be solved by the vendor, currently.
- U310, U410, U510, U410 Touch, U310 Touch;
- Z500 Touch, Z500, Z400, Z400 Touch, Z380, Z480, Z580, Z485, Z585;
- S300, S400, S400u, S400 Touch, S405, S206, G485, G585, N480.
- The following models do not support upgrade to Windows® 8.1:
- Y480, Y485, and Y580 with the SSD+HDD configuration;
- S206 equipped with CPU other than E450, E300, E1-1200, E2-1800, or C60.
- Yoga 11 is equipped with a Windows® RT system and only supports upgrade from Windows Store.