The flexible stainless (?) pads that serve as battery contacts sometimes break. Many people report that Garmin has repaired this at no charge even if the units are out of warranty.

There have some reports of units not really being waterproof. The reality is that once water is inside it, it's probably toast. Success in getting this fixed out of warranty seems to be mixed.

Hold the ENTER key while powering up with POWER. Hold both until the test screen appears. That screen lets you test each button. Press each key, one at a time, to see if it's recognized. If your key isn't recognized here, it probably needs a field trip to the Garmin service center.

This is great fun to find if you have your device muted. You won't hear the beeps, but the unit doesn't actually shut down. Your only sign that this happend is that the batteries will likely be dead when you next go to use the GPS.

This family of products contains a defect in the shutodown code that seems to be intermittently triggerd by mounting the product or its SD card on a Mac or Linux system. The presence of files starting with a dot on the GPS seems to cause it to crash when shutting down.

You usually can't delete these from withing the GUI tools like Finder. You'll have to do it from a shell prompot. On Mac, open Applications->Utilities->Terminal. cd /Volume/[name of your disk as it appears in Finder then type rm -fr .Spotlight-V100 .fseventsd .Trashes to remove the files. cd / and eject the volume. On Linux, the filenames and commands to remove them are similar.

There are mixed reports of this being fixed in some models in late 2009 vintage firmware.