I have a 2005 330Cic with MKIV NAV System. I've searched and read numerous posts about "nav issues" but none of them seem to address the issue I'm having.

Start the car and the NAV works without any issue - no "please wait" messages, error messages, etc. Can enter address, start guidance, drive, and experience no problems.

If I shut off the car (to get gas, for example), the Nav system will display "Error Reading CD/DVD." The issue does not resolve itself while I'm driving. There are no issues with using any non-nav function.

When I shut off the car for an extended period of time (more than 60 minutes), the NAV system again functions, but the address entry is completely blank (have to select country, state, etc. all again) and does not display the last used address.

This issue just developed about 2 months ago and is consistent and reproducible. There have been no changes to the vehicle or the NAV computer during this period.

Any help is appreciated. Thanks in advance.