Just got home a bit ago and the download went zooooom, in seconds done, but being my Insider preview is in Hyper-V and I'm playing music, checking out the forums....etc the installation took a little bit longer to do(I have time) than usual.
Only once I had problem with applying upgrades and quick re-apply fixed it but it's second time windows showed that they are not activated. Quick trip to activation fixed it. No idea why it happened twice in a row now as I'm registered with same account since W7 !!!!
Installed new build (upgrade) to 14291 from 14279 all went ok and 14291 is running ok. DISM is now working but SFC is not.
Up and running in an hour. Missed it last night just for few minutes . Better this way. I'm too old for sleepless nights.