Something went wrong. The device is already enrolled. You can contact your system administrator with the error code 8018000a. A different user account on this Windows installation has already connected a work or school account — either an MDM enrolment or a Microsoft Entra join. Windows allows one such connection per device, so the second user is refused.
8018000A
The device is already enrolled by another user
What it means
Common causes
A different user profile on the device has already enrolled it in Intune or joined it to Microsoft Entra ID.
A shared or hand-me-down device still carries the previous owner's work or school connection.
How to fix it
Check Settings > Accounts > Access work or school. The message Another user on the system is already connected to a work or school confirms the diagnosis.
Sign out of Windows and sign in as the account that made the original connection, remove the work or school account under Settings > Accounts > Access work or school, then sign back in as the intended user and enrol.
For devices changing hands permanently, reset the device rather than unpicking profiles — it is faster and leaves no stale device records.
Frequently asked
How do I tell which user made the original connection?
Run dsregcmd /status as each signed-in user. The User State section shows WorkplaceJoined per user profile, and Device State shows whether the device itself is joined — a device join affects everyone, a workplace join belongs to one profile.