Schema Synchronization Hangs Indefinitely When Publishing Extensions to Production-Based Sandbox Environments

Question

We are unable to publish AL extensions to any Sandbox environment that has been copied from our Production environment. The publishing process hangs indefinitely during schema synchronization and never completes.

Symptoms

1. Publishing stops at the API call: https://api.businesscentral.dynamics.com/v2.0/Test/dev/apps?tenant=000a1867-654d-4d8f-a74a-494e5f1e05c4&SchemaUpdateMode=forcesync&DependencyPublishingOption=default
2. The process never times out or returns an error - it simply hangs forever
3. This occurs regardless of SchemaUpdateMode used (Synchronize, Force Sync, or Recreate)
4. The issue persists even after uninstalling the old version of the extension from Extension Management

What Works:

• Publishing to a new, empty Sandbox (not copied from Production) works perfectly
• The same extension and code publish successfully to clean environments
• Authentication is successful (user: ******@alliancelwala.onmicrosoft.com)

What Doesn't Work:

• Publishing to any Sandbox copied from Production hangs indefinitely
• This occurs even after:
  • Uninstalling the existing extension
  • Clearing credentials cache
  • Restarting VS Code
  • Using different SchemaUpdateMode settings

Business Impact

• Unable to test extensions with Production data before deployment
• Cannot validate extension upgrades in realistic environment
• Blocking our development and deployment workflow
• Concerned about potential issues when deploying to Production environment

Troubleshooting Already Attempted

• Cleared credentials cache
• Tried different SchemaUpdateMode options (Synchronize, Force Sync, Recreate)
• Uninstalled old extension versions before publishing
• Restarted development environment (VS Code)
• Created multiple fresh copies from Production (issue persists)
• Verified network connectivity and firewall settings
• Confirmed publishing works to empty Sandboxes
• Used latest AL Language extension

Questions for Support

1. Are there any known issues with the Production environment database that could cause schema sync operations to hang?
2. Is there orphaned table metadata or corrupted sync records in the Production tenant database?
3. Are there background processes or locks preventing schema modifications?
4. Can you check the health status of our Production environment and tenant database?
5. Are there any diagnostic logs you can access that might show why the schema sync is hanging?

Answer 1

Thanks for reaching out!

This behavior matches a known issue in Business Central where schema synchronization can hang indefinitely in Sandbox environments that are copied from Production.

In such cases, the problem is not related to the AL code, schemaUpdateMode, VS Code, or network configuration. It is caused by inconsistent or locked schema metadata in the copied tenant database, which cannot be diagnosed or resolved from the extension side.

This causes due to

Publishing works in empty Sandboxes. The issue persists even after uninstalling the extension. The publish operation hangs without returning an error.

Unfortunately, there is no developer-side fix for this. The resolution requires Microsoft to inspect or repair the tenant database.

You can try below points

Create a new empty Sandbox for testing schema changes or Raise a Microsoft support ticket and request tenant-level investigation/repair for the affected Sandbox copied from Production.