MMI "initialising"

[Dippy]

I have noticed that sometimes when I start my car the MMI comes to life pretty quickly but other times I see "initialising" screens. Not just sat nav but media and car systems as well. Has anyone got any ideas about why it is sometimes slow to start?

Note: I am not referring to it getting stuck or taking a particularly long time, just that sometimes I see the screens and sometimes it seems to start straight away.