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The Nuvi might perhaps be still searching for information. But, after 2 hours, I suspect it has simply locked up.
It might be best to wait another hour or two, but disconnect it, turn it Off for 20 minutes or longer, restart the computer, re-connect it, and try again.
Let me know how it goes, please, in Reply To Expert. (And if this completes the case and answers your question, please rate my answer.) Thanks.