Whenever I plug the Navman into an ext power source (including car cigarette lighter) it just shows Navman to USB to Computer icons and will not come on. As soon as I disconnect it work fine, in other words it only works on internal battery power.

SOURCE: Screen is showing computer, usb

The F20 Desktop Software and Service pack on the CD's from navman do not work, as you have seen. The solution is to go to the navman website and download this Service Pack

Be sure your f20 is connected to the USB cable and turned on displaying the USB Connection screen. Leave it on during the entire process.

Once downloaded, run this self extracting file and let it install automatically. After it is installed and ran.....you will see the same error again of failure to connect.

At this point you must reinstall the driver manually. Right click on your "My Computer icon, Select Devices, then properties on the navman. You should see a yellow "?" next to a statement "Unknown Device" in the USB devices. Click on the "Reinstall Driver" and select a specific location or the Have Disk button. The USB driver is now located in C:\program files\Navman\f20servicepack\USB directory.

You should get a button that now says Okay at the bottom, click onto it and allow the MS program to update the drivers. You should see the device screen change and say "This device is operating properly". You can then close the windows and run the F20 desktop program. It should connect then.

SOURCE: have a navman f10,do i

rang technical support and they explained everything

SOURCE: f20 navman error

I have had the same problem and did what gossages recommended and it worked straight away thank you very much!!!!

SOURCE: navman wont start

well does it have an AC inlet to charge it? If so use it rathyer than DC car charger to revive a depleted battery. It will take an hour or so to get up enough power to turn it on and a few more hours to get a decent charge into it. Life of battery in unused state is around 3-4 days depending on condition of the battery. Total depletion will take some time to get the battery to recover siufficiuently to get basic operation to occur. Be patient and if this fails to fix it try replacing the battery altogether

SOURCE: Navman model no N197 -

Base from the description of your problem what we need to do here is to reset your unit and to do that follow this , there is a small hole at the back of the unit (from memory, but might be on the top) just use a pen to press and hold it for 10 seconds and then restart the unit and check if its back to original state.