Welcome to Justanswer.com, my name is Dustin.
I'm sorry to hear about the issue you are having, I will do my best to help you resolve it.
If you have a backup in your garmin express program, then you can restore that data from a backup.
Id launch garmin express, connect your Nuvi. And then see if it has a backup you can restore..
If not, then the other option is to connect the garmin to the computer.. Open it up inside windows explorer.. And then look inside the garmin drive for a current gpx or temp gpx.. If the files is still present, make a copy.
Then reboot the garmin, and then copy that file back onto the garmin.. That should do the trick.
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