Revert to VAB doesn't work if you load in a saved game?

[Paulyuk6]

If a rocket blows up on the launchpad, I can quickly Revert to the VAB to fix whatever the problem is. But later in the game, I am find that Revert is no longer available - especially if you load in a previously saved game.  It is hugely frustrating!

For instance I managed to get a craft into orbit. I then saved the game shut down and went to lunch.  When I came back I loaded the game in again, and then when I try to set sail for the Mun, I discovered my fuel levels were too low.  So I thought I could revert to the VAB to add more fuel but found that I could no longer do that. I can only resume from the point at which I saved.
Is this deliberate or is it a bug waiting to be fixed?

Paul

[Gargamel]

That was how KSP1 worked, I believe this is the intended behavior.    It does have upsides though.    Now you get to perform an unplanned re-entry,  or mount a rescue mission.     To me, that adds to the game play and overall enjoyment.