I purchased a 2004 Mini Cooper S. The car came with only 1 key. The previous owner do not know where the other key is at. Is there a way for me to disable the missing key. I want to make sure I do not walk outside and my Mini is gone .

 

I believe the dealer can deactivate any missing keys. The holder of a deactivated key will be able to unlock your door (obviously), but not start the engine.

 

If you buy a new key, all current keys will be reprogeamed by the dealer...as said before, the old key will be deauthorized, and can open a door, but not start the car.
You may wish to order a valet/plastic key from the dealer as an emergency key...still $$, but cheaper than the $200 or so fo a new one.....

 

I have an 04 S and dealership told me existing keys for my car cannot be deauthorized, only later models.

(My keys were taken.)

Only option available to me, according to him, was to change out all locks/ignition at around $1,000.

You're not necesarily being scammed here. It's not entirely impossible that the previous owner got by with one key. I did for 3 or 4 years after the spouse lost the spare set. and then someone took that set, and I was well and truly stranded. A real criminal mind might have purchased a spare key in order to give you two and then with your guard down come in and taken the car.

Let me know if you are able to get pervious keys deauthorized. It wouldn't be the first time someone at a dealership had got something wrong.

 

My current solution is to install an auto alarm, (As you can see from my other post). I also plan to have the ability to switch off the fuel pump with an hidden switch. This is my current plan until time past by and I feel my comfortable with the fear that some one might have an extra key.