TriggerFinger

I have seen a lot similar to this... not only for a D600.. just Google 'dell adapter not recognized' unfortunately DELL has no definitive answer. Does your battery continue to charge even with the message?

The solution range from adapter replacement to motherboard replacement. I also have read that you can suppress (disable the option) the message in the BIOS. I would definitely start with this (disabling the message option).

I know you can bypass this with an F1 just make sure your battery continues to charge.