If it's a software corruption problem you can try a couple of options:
1)Downgrade firmware to a previous firmware and then reinstall the current. Downgrading it will clear NV completely.
2)Backup Edge content on pc, then format it as FAT32 following this thread:
[Only registered and activated users can see links. ]
Remove the SD card if present before formatting.
When done, create a new folder named "Garmin" in the newly formatted drive. Restart it and run Webupdater. Add missing files from backup, don't add back Courses and Activities files and any personal data files.