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Data Corruption in Workflow TaskInstance Table Causes Incorrect Approvers After Major Upgrade

Umbraco Workflow Version: v17 During a multi-stage major upgrade of Umbraco CMS and Umbraco Workflow, missing database relationships can cause severe UI and tracking anomalies in the back office.

Written by Joana Knobbe

This occurs when specific historical workflow records contain null identifiers, confusing the workflow engine's in-memory data caching and leading to misaligned user assignments in both active and historical logs.

Issue: After upgrading Umbraco CMS and Umbraco Workflow from v13 to v17 (via v17.1), the Workflow section in the backoffice experiences severe data misalignment. While the underlying workflow configuration steps appear correct, the workflow detail views for both active tasks and history display incorrect approval group members and mixed-up approvers across all workflows.

This behavior is triggered by rejected approvals that required a resubmission prior to the upgrade. In these specific scenarios, rows in the WorkflowTaskInstance database table are missing critical schema data, leaving the GroupId field as NULL. This structural discrepancy conflicts with the strict data expectations of newer versions, causing the system to improperly map historical task states.

Solution:

To resolve the incorrect approver listings and repair the corrupted historical records, you must perform a schema health check and manually fix the orphaned database rows before finalizing your upgrade:

  • Step 1: Inspect the Database for Schema Anomalies
    Run a query against your database to check for orphaned task instances containing NULL fields in legacy task states:

    SQL

    SELECT * FROM WorkflowTaskInstance WHERE GroupId IS NULL

  • Step 2: Identify and Map Missing Groups Analyze the returned rows—specifically checking for historical records corresponding to rejected approvals with resubmissions. Trace these records back to their original workflow context to determine the proper group association.

  • Step 3: Manually Update the Table Apply an update script to populate the missing GroupId fields with their correct, corresponding approval group IDs, effectively resolving the data model conflicts.

  • Step 4: Re-run the Upgrade Staging Once the database schema relationships are restored and no orphaned NULL group values remain, proceed with completing the upgrade process to the latest versions of Umbraco CMS and Workflow.

Article last update date: 18-05-2026

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