Error code

Xbox E100

XBOXE100
Game/Platform Error· An error code shown by a game or gaming platform/launcher.

What it means

The console failed to complete a system update..

How to fix it

  1. Power cycle the console.
  2. Use Xbox Startup Troubleshooter to run Offline System Update via NTFS-formatted USB.
  3. Factory reset via Troubleshooter (Remove everything).

Not affiliated with Xbox. Answer summarized from the manufacturer's manual linked above; consult that source for the authoritative procedure.