Quote Originally Posted by catymag View Post
Nuvi hard reset procedure

Spoiler: click
Master reset on nuvi 34xx, 35xx, or 37xx series devices :

1. Power off the unit (press/hold the power button for ~7 seconds)
2. Power on the unit
3. When the Garmin copyright screen is displayed, press & hold the bottom-right corner of the screen
4. Release the screen when "Do you really want to erase all user data?" appears
5. Touch "Yes"

Alternate method:
1. With the unit powered on at the map screen, press the bottom-right "Speed" field which will take you to the Trip Computer page
2. Press/hold the area just above the numerical speed on the round speedometer dial (where the compass heading is displayed when moving)
3. After pressing this spot for ~7 seconds, you will enter diagnostics mode
4. Select the first option displayed "Clear all user data", then follow the prompts

Reset all your location settings and user preferences. Also restore your favorites using the method outlined at the beginning of this post.

If possible after the hard reset (all units), let the unit sit outdoors in the open for about 30 minutes or so to let the unit re-acquire satellite almanac data.

Both methods worked with my 3590LMT. And on the Garmin website, it states method #1 works for the nuvi 34xx series as well.
hxxps://support.garmin.com/support/searchSupport/case.faces?caseId={80c3c390-85f1-11df-f376-000000000000}