Does your 3597LMTHD have a Trips folder?

I don't have a 3597, I have a 2460. Both these units use "TRIP PLANNER". I do have a Trip folder inside the System folder.

I suspect whatever software you used to create the route it corrupted the files due to incompatibility with units using Trip Planner, thus the gibberish you see. As an experiment use the Trip Planner on the 3597 and create a short route to test. Give it any name you want and save it. Now look in the Trip folder and see if it appears with the name you gave it and try to save it.

Thanks. I also have a Trips folder in the .System folder. There are several legitimate trips in it. Some seem to have been created from the MS Trips and Streets, that I exported as .gpx and then manually copied to the GPX folder. Another was created with MapQuest and Sent to the 3597. I tried using MapSource, but it doesn't even see the 3597. I'm not sure if any of these actions created the rogue Trips folder. All of the trips display in the Trip Planner.

I did as you suggested and the Trip Planner saved the trip in the .System\Trips folder.

As far as I can tell, the rogue Trips folder that's at the root level of the internal disk is not causing any problems with normal operations, but I wonder about any software such as Garmin Express and BaseCamp. They also seem to be working okay at the moment.

I used the robocopy command to copy all the folders and files excluding the rogue Trips folder from the internal to an external disk. Now, do I try to delete the rogue Trips folder? (i.e. how much of a risk taker am I!!)

I am a risk taker. Since you can't backup the files I would delete the rogue folder and it's contents.
I wouldn't anticipate any problems with the Nuvi's normal functions if choosing to do so.
Hopefully you can delete the folder.

Have you tried backing up the trip you created in Trip Planner? If you did, once you've deleted the Trip folder create a new one in the System folder and copy the backed up file there and test it.

I always make a backup of my trips, if memory serves me correctly (seldom), after doing a hard reset I recall losing the Trips folder and contents. I simply copied it back from my backup and all is well again.

As I suspected, the rogue Trips folder cannot be removed with F:\> RD /S Trips. It gets numerous filename, directory name is incorrect errors.

Unless there's another way, the next step would be to format the internal disk and restore from the backup hoping that robocopy got every bit of info the 3597 needs. Have you ever formatted and restored?

Mapsource will not open a Trip, even if it could see your 3597. My first thought was that maybe your 3597 is in MTP mode but since you can see the .system folder that can't be the reason Mapsource can't see the device, unless you used the option to only use USB mode until the device was restarted. If that's the case, check to see if you can still see in the .system folder and if you can't then that maybe the reason Mapsource doesn't see your Nuvi.

The rogue Trip folder sounds very much like file system corruption which probably only a format and restore is going to fix. Although it can be done, and I'm a bit of risk taker, I personally wouldn't do a format of the drive it the rogue folder isn't causing you any further issues.

Personally I've never formatted any of my Nuvi's.
However I once had a problem with my Nuvi displaying far less memory then it had. I called Garmin Support without any solution.

I then used windows "chkdsk" on the Nuvi drive and it found the problem, deleted the files, and restored my lost memory.

You could also try downloading some free software such as FileAssassin to delete stubborn files you are unable to delete. I would try that before chkdsk.
Maybe somebody could advise a reliable program to delete the corrupt files or do a Google search.
I've tried FileAssassin in the past and didn't always work.

I tried DelinvFile to delete one of the invalid files within the rogue Trips folder, but it failed because of the invalid characters.

Until I know that others have successfully formatted and restored, I think I'm with t923347 and will charge on until it fails to perform or won't update.

Thanks for the clue as to why MapSource didn't see the 3597. At the time I tried to use MapSource to retrieve data from the device, it was in MTP mode. Later, when I wanted to backup up the 3597, I switched to Mass Storage mode. Now, in Mass Storage mode, MapSource sees the 3597 and will retrieve data.

My curiosity got the best of me. I used CHKDSK to fix the problem of the garbage Trips folder in the root of the internal drive.

But, not before taking the precaution of using Passmark's free utility, OSFClone, to make a bit-for-bit clone of the internal disk to a 8GB USB flash drive. I ran CHKDSK /f on the clone. It found an unrecoverable error in the Trips folder. I let it convert the folder to a file. Afterwards, I deleted the file. Satisfied that CHKDSK wasn't going to trash the drive, I then performed the same steps on the 3597 internal drive.

Everything is still working and I didn't have to format and restore.

Great job. And others have said that check disk won't work.

I'm glad you took my suggestion of running chkdsk.
As I stated it worked for me. I'm very impressed you went the extra cautious mile to test it first on the flash drive. Good job, thanks for letting the forum know of your success and perhaps helping others with a similar problem.