Just a quick heads up to anyone with OS maps on their Garmin’s. Hopefully will help prevent anybody else making the same mistake I made recently.

Last week I was installing some free source maps on to my Garmin. The DC Rainmaker website said to make a copy of the map file already installed on the SD card on your PC before making any changes. In my case it was the OS maps file. So, after I’d finished messing about I tried to re load the os map back onto the SD card. However, the Garmin simply couldn’t find it. After getting in touch with Garmin they suspect the file is corrupted. Any such copying/moving on or off the card will apparently destroy the file. I can only assume it’s to prevent piracy.

Garmin have offered to re load the maps for £30 if I send the card along with proof of purchase. Still, a bit annoying!

Yeah, you can’t touch them. It’s really annoying that you can’t even back them up given how expensive they are.

Always put a fresh card in if you want to mess about.

I have copied my OS maps from one of my Garmin 800’s to the other. I also have OSM maps and OS maps both on the same SD card and can switch between the two on the same Garmin 800.

Did you remove the file from the SD card though? According to Garmin that’s the issue. At least with those supplied by garmin.

Licensing for the Garmin maps is ridiculous and I certainly won’t be buying from them again! Depending on whether you buy via download or on SD card, the maps are either locked to a specific GPS unit or a specific SD card.

There was software available on the internet (although I’ve never used it) that would unlock the maps but I’d guess that it’s don’t considered legal to use it.

I’ve used it – guilt free – so I can make backup copies and/or move it to a bigger SD card.

The map file is probably fine it’s likely you overwrote the licence file. Use the (illegal) software to restore your legally purchased property to working conditions. No court outside the US will have issues with this behaviour. In the US the DMCA will get you for circumventing encryption but elsewhere common sense tends to be used.