Problem

Metasys 11 server stops working after automatic Windows update to Windows 11. Log-in fails or system becomes unresponsive. Error mentions "Dictionary Service" or authentication failures.

Root Cause

Metasys 11 is not certified for Windows 11. OS version mismatch causes library/API compatibility issues.

Solution

Short-term (Get Running Again)

1. Downgrade to Windows 10 (if still supported):

   • Backup all Metasys databases and config files first
   • Use Windows rollback feature (if still available within grace period)
   • Alternatively, completely reinstall Windows 10 on the server from installation media

2. If rollback not possible:

   • Contact JCI support for an extended compatibility patch
   • They may provide a workaround or hot-fix

Long-term (Permanent Solution)

1. Upgrade Metasys to version 12 or 13:

   • Version 13 is fully certified for Windows 11
   • Version 12 has partial Windows 11 support with some caveats
   • Schedule upgrade during maintenance window (can take 4–8 hours)

2. Prevent automatic OS updates during business hours:

   • Disable Windows Update automatic restart
   • Schedule updates for after-hours via Group Policy (if domain-managed)

3. Document your OS/application versions in your asset management system