I think I am experiencing the same problem as others. 2005 X3 3.0, 27K miles, CPO and still under factory warranty for a month. Just got it last Thursday night. Sadly I have been unable to drive it.

When I tried to start the car Friday morning, the dash lights all lit up as normal prior to starting, but the starter never started. No clicks, no whirring, no sputter, no cranking, nothing.

I tried to start the car numerous times over the next hour. No changes.

Moving the gearshift into N did not help.
Using the valet key did not help.
Turning off every accessory (or turning them on) did not help.
The stereo works fine, as does the nav, blower, AC, etc.

The battery does not have a green dot (it's black) but the load test performed by the dealer during CPO shows it is OK, at 12.5V.

So I called BMW Roadside and the guy came and we tried starting it again. 10+ tries with same results as above. The tow truck lowered its ramp and got ready to pull the car up the flatbed ramp.

Out of the blue, on one final attempt the car started. The tow truck driver and I were shocked. After letting the car run for a minute, we turned it off again, and it failed to restart.

After a few more tries, it started again, and I left it running. I drove it to the dealer figuring they might as well fix it before I get stranded someplace other than home.

Of course when I was at the dealer, the car started flawlessly every time. The car has been looked at each of the last 3 days and has started fine each time...

I've asked the dealer to swap out the ignition switch but they are reluctant to do so.

Any suggestions on how to troubleshoot this or tell the dealer what to look for? (They downloaded the codes but the codes told them nothing.)

-pd.