USB device not recognized

The fact you're being told that the cable cannot charge your device suggests a faulty cable or the port on your nuvi. Does it charge if connected to its car charger? If it does that would rule out the port.

If the port is ok try setting your nuvi to mass storage rather than mtp mode, that can often resolve connection issues.

Hello and thanks for the response. Since I tried multiple cables that all function well on other devices, I think I can rule out the faulty cable. It charges fine in the vehicle in its cradle using the car charger. But the last suggestion is interesting. Could you explain how to change to mass storage? I've looked at all the categories on Nuvi and don't see that as an option anywhere. I also opted to 'Restore' but that didn't help.

I googled the method of changing to mass storage and did that--but it still is not recognized. Thought that might be the solution darn it.

If that hasn't worked I'm out of ideas, sorry

Thanks for the suggestion, but I'm reluctant to run the repair tool since I'm not familiar with what changes it can make and I have a history of things going from better to worse using repair tools! Since my computer's USB ports function fine with all other devices, I don't think the computer is the issue anymore. I think maybe the port on the Nuvi might be faulty and I don't know how to fix that. I guess I can just forget about map updates through Garmin Express and use the Nuvi until it quits working entirely.

The repair tool won't make any changes unless it find issues.  You'll also note that it comes directly from Microsoft and is many years old.  I can assure you it is bug free and can fix issues and only takes a few minutes to run.  Garmin Express uses the .NET framework to work properly so it is essential that .NET function properly.  

As an aside, if you are reluctant to run such a tool to insure that something is working properly, how do you expect people to render assistance?

You can view a video on repairing the USB port on the device should you ultimately think that the issue.  See Repair Garmin USB port

I waited to reply until I received my replacement Garmin cable, just in case that was the issue. It wasn't and I had tried many other similar cables with the same bad result. 

The reason I am reluctant to try unfamiliar software is predicated on undesirable results in the past. I appreciate any suggestion I receive--but do not feel obligated to try each and every suggestion. I tend to prioritize based I my own opinion of what the solution might be. I did run the .NET framework today to no avail. 'The tool was unable to resolve the installation issue'. 

I do feel the most likely culprit is the usb port on the Garmin and the video link might be the answer. I haven't viewed it in its entirety, but right away the author mentions the port issue is common. I have a good feeling about this--but have to get motivated to spend the time disassembling the unit.

Thanks for your help.

If you want to consider a repair facility review the content at palmdr.com.

That's good to know. Their prices seem reasonable and I'm sure they would do a better job than me. Thanks for doing all the research! Wonder how they can do the repairs so reasonably?