Cut a wire coat hanger into four pieces and shove each piece in one of the holes on the corners of the nav computer. That will release the lock clips and it will slide out. (Some times it takes some effort to wiggle it out.)

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SOLD
2000 E38 750iL Highline Edition, Upgraded with the lastest 2006 X5 Electronics
MKIV Navigation, 16:9 Display, Bluetooth, TV/Video with Backup Camera, Sirius, and Aux Input