microsoft arc mouse keeps dropping from Dell Latitude 7420

Try this order:

1. Re-pair the Arc Mouse
   • Remove the mouse from Start > Settings > Devices > Bluetooth & other devices.
   • Press and hold the pairing button on the bottom of the mouse for 5–7 seconds until the light blinks.
   • Add it again from Add Bluetooth or other device > Bluetooth.
   • If the pairing light flashes three times and turns off, the mouse is already paired to another nearby PC. Remove it from that PC first, then pair it again to the Dell Latitude 7420.
2. Check power first
   • Press the pairing button for 5–7 seconds.
   • If the light does not come on, replace the batteries.
3. Reduce Bluetooth interference
   • Turn off other Bluetooth devices connected to the laptop and test again.
   • Too many Bluetooth devices connected at one time can interfere with the connection.
4. Toggle airplane mode
   • Turn airplane mode on for 10–15 seconds, then turn it off again.
5. Turn off Battery Saver
   • Select the Battery icon on the taskbar.
   • If Battery Saver is enabled, turn it off because it can interfere with Bluetooth connectivity.
6. Disable Bluetooth power saving
   • Open Device Manager.
   • Expand Bluetooth.
   • Right-click the Bluetooth device, select Properties.
   • On the Power Management tab, clear Allow the computer to turn off this device to save power.
7. Restart the Bluetooth service
   • Press Windows key + R, type services.msc, and select OK.
   • Right-click Bluetooth Support Service and select Restart.
8. Update Bluetooth drivers and Windows
   • In Device Manager > Bluetooth, right-click the Bluetooth device and select Update driver.
   • Also check Start > Settings > Update & Security > Windows Update and install available updates.
9. Test the mouse with another PC
   • If it works normally on another PC, the issue is likely with the Dell Latitude 7420 Bluetooth connection.
   • If it also drops on another PC, the mouse itself may be the problem.
10. If the delay happens only after inactivity

• Bluetooth mice can hibernate after 8–10 minutes of inactivity to save battery.
• A short reconnect delay of several seconds after that is expected behavior.

References:

• Troubleshoot problems with your Surface mouse or keyboard | Microsoft Support