For posterity, I realise I have been bitten by this.
Updates may have an "on startup" component to them. If you shut down, currently you are forced to install updates on the shutdown - this happens silently, without permission. But: It will just do the shutdown side - so that the next time you start, you're stuck there looking at the "startup part" where updates continue to install.
MS ought to fix this, either by changing how updates are installed in two phases, or to incorporate an automatic "shutdown/install"=>"start windows, run updates"=>"shut down" option.
Also they should let you just shut down the PC without having to install updates, especially if you don't have time to do so.
Currently, as a user, the only really safe thing to do would be to "update and restart" followed by a shutdown.
Updates may have an "on startup" component to them. If you shut down, currently you are forced to install updates on the shutdown - this happens silently, without permission. But: It will just do the shutdown side - so that the next time you start, you're stuck there looking at the "startup part" where updates continue to install.
MS ought to fix this, either by changing how updates are installed in two phases, or to incorporate an automatic "shutdown/install"=>"start windows, run updates"=>"shut down" option.
Also they should let you just shut down the PC without having to install updates, especially if you don't have time to do so.
Currently, as a user, the only really safe thing to do would be to "update and restart" followed by a shutdown.