I purchased this Navman from Amazon. The Navman literature states that it is compatible with Palm OS 5.0 and higher. IT ISN'T !!! I have the Palm Tungsten T5 which has Palm OS 5.4.I have talked to people at the company and they admit it isn't compatible with Palm OS 5.4. Also they have no idea when a "fix" will come out. They seem to have a don't care attitude. DON'T BUY THE PRODUCT.