How does one delete the Track Log on a 50LM?

Good question. I don't think it can be done since it is really stored in the Nuvi's internal memory. Even if you clear the Current.gpx file it will still be there after you restart the unit.

Another brilliant move by Garmin, appears a master reset is needed instead of just adding the option in the firmware.
Make sure your favorites are backed up. All this extra work and time to do a simple chore.

http://support.garmin.com/support/searchSupport/case.faces?c...

To clear the trip log on a nuvi 30, 40, or 50 series device:

You will need to perform a master reset.

Note: A master reset could erase all waypoints or favorites and will restore your device to the default factory settings. If you would like to back up your favorites to your computer, you can find instructions to do so here.
Start with the device off and unplugged from power
Touch and hold the lower right corner of the screen with an index finger or the eraser of a pencil
Continue touching and holding the lower right hand corner of the screen then power the device ON
Release the power button when the device powers ON
You will see a new message: "Do you really want to erase all user data?"
Remove your finger from the screen when this message displays
Touch Yes
If text language is not in English, this is the button on the right
The device will now reset. Follow the on-screen prompts and then place your device in an area with a clear view of the sky until it acquires satellites.

It really does stretch credibility that Garmin could believe that was an appropriate action.

I wonder what happens when the storage is "full"?

All that is just not worth the effort for me. I think the only reason Garmin protects the tracks is so that they can use the data for "evaluation" if you check the "send anonymous usage data to Garmin" option on the Garmin Dashboard page or in GarminExpress.

IT only stores a limited amount of tracks. I think, but not sure, that it is based on how old the tracks are.

Couldn't you delete all the tracks on a Nuvi without a reset by running Garmin's Basecamp software with the Nuvi attached to the PC? Import the current.gpx file into Basecamp, delete the tracks, and export the altered file back to the Nuvi.

I'm confused as to how a reset would help you delete tracks anyway. To save your favorites you'd save a copy of the current.gpx file to your computer, rename it, and after the reset, copy the renamed file back to the gpx folder on the Nuvi. Wouldn't putting that renamed file back on your Nuvi place all your favorites, tracks, and saved routes right back on the device since you haven't altered the contents of the orginal current.gpx file which contained all that data, you've only renamed the file?

Have you actually tried this? I have.

After you clear the current.gpx file of tracks, save it, and copy it back to the unit. Turn the unit on and let it load completely. Turn the unit off. Check the current.gpx.

Wanna guess what is there?

Do you think Garmin ever reads these posts? More important, do you think they ever make improvements based on what they read?

No. Like any big company they have their own agenda and priorities. And why should they when they can weigh the number of forum members against the number of total units sold worldwide. It's not really the best use of their manpower and time.

We must persevere and learn to deal with the flaws.