This article provides steps for performing a hard reset on an Elo M50 device

All user data will be erased and the device will be restored to factory settings. 

1. Power Off device
2. Press POWER key until Elo splash screen appears, then Hold LEFT Volume Up key 
3. Continue holding LEFT Volume Up key until unit starts Android System Recovery
4. Press LEFT Volume Up key to select "wipe data/factory reset"
5. Press POWER key to select
6. Press LEFT Volume Up key until "Factory data reset" is selected
7. Press POWER key to select
8. After data wipe is complete, press POWER to "reboot system now"

Also, see our knowledge article: Perform Factory Data Reset on M50 Mobile Computer