For example, an outdated firmware issue left some Surface RT tablets unable to boot up after users installed the OS update. That took several days to fix and during that period Microsoft pulled the update from the Windows Store.
In addition, as IDG News Service first reported this week, the presence of some outdated drivers and incompatible software has made it impossible for other users to complete the Windows 8.1 installation, another issue Microsoft is looking into that started affecting users on the day of the OS' launch.
Moreover, another group of users who own older PCs that are able to run Windows 8 can't install 8.1 because the update has additional hardware requirements, as reported by PC World.
Juan Carlos Perez covers enterprise communication/collaboration suites, operating systems, browsers and general technology breaking news for The IDG News Service. Follow Juan on Twitter at @JuanCPerezIDG.