On the BMW MkIII and MKIV navigation systems, if you downgrade to an older software version and then reinstall a newer software version (such as going from V23 down to V22.1 and then back to V23) , the navigation system may reset out of USA mode and put you into UK mode which results in the elimination of the “Accept” screen from your system.You will know this has happened if (1) you are receiving directions from your system in yards instead of feet, (2) the “Emergency” option has disappeared from your main menu, and (3) your radio and CD screens will not appear as splitscreen.To reverse this, the dealer must hook the vehicle up to their computer and recode the navigation system to “USA” mode.There is also a module that has been developed and is being sold which intercepts the i-bus command and will send the “Accept” command to you on your behalf. For more details on this solution, see the web site http://www.bmw-accept.com/