As GPS devices are used, data is gathered which helps them acquire satellites quickly at the start of each use. If a device is used daily it should be able to acquire satellites in a minute or less.
Often though, we've had several devices intermittently lose signal during a ride, and on rare occasions, not find a signal at all.
It could also be accompanied by a device lock-up, which the Garmin tech's believe to be purely coincidental, so we'll go with that and treat them separately.
Simple fix to restore a lock up.
Power down the unit, remove the battery, wait a few minutes and put the battery back in.
Yep, pretty high tech stuff we know, but that's all it takes. (usually)
Losing signal or not acquiring satellite.
There's many reasons a GPS may lose satellite, if it's only on rare occasions it could be considered normal.
However if it happens regularly, try these steps.
1. Update it
Update to the latest version of operating software by using the Garmin Express program.
If this doesn't resolve the issue, perform a master reset.
Remember that a master reset will restore your device to factory settings, so you'll need to reconfigure any customised layouts etc, Before performing a reset, it's a good idea to back up or save all of your data via basecamp or treating it like an external drive and saving the files to a folder on your desktop.
2. Master reset
Make sure the device is off, not just in standby mode.
Press and hold finger on upper left side of screen (Outdoor devices ie: Montana) or lower right hand (Others, ie: ZUMO) this can be done in portrait or landscape mode. see pics below
Power on device.
Continue holding until the Do you really want to erase all *user data? message appears.
Release finger from the screen.
Allow device up to 20 minutes to acquire satellite data with a clear view of sky
The device is now reset and ready for use.
*User data consists of waypoints, routes, tracks, and geocaches.
Montana and outdoor devices - Press and hold top left of screen while powering on device.
ZUMO and Automotive devices - Press and hold lower right of screen while powering on device.
Touch Erase and allow the device to reset.
If your device continues to have problems, contact Garmin support