Board Thread:Warhammer 40k General Discussion/@comment-73.173.194.135-20141127163628/@comment-88.202.171.162-20151213221358

It would seem that the 'power' only works in a death state. The Emperor isn't truely dead so can't use it. The Golden Throne keeping him going. If he was allowed to die then that would be a different situation. So really he is in limbo.

That said, it's not confirmed and he might have been 'diabled' by Horus's attack. Lot of the material is subject to rumour and older lore which may or may not be changed by the HH books, Quite looking forward to reading those, though they seemed to have stalled to story slightly, likely to sort out the 'facts' at GWS HQ before writing.