I purposely ordered our X5 without the Comfort Access. Between my wife having problems with another brands' (Toyota) version of Comfort Access, and the dealer admitting that 'there had been a few issues', I left it off.
My wife must have some type electrical interference in her body. LOL. She can only wear mechanical wristwatches & anything with batteries near her dies quickly. So no Comfort Access for something she drives.
Am sorry that some of you are having issues with it. Call me old fashioned, but I'll stay with the traditional key fob to unlock & key for the ignition for the foreseeable future.