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The error message, "Error: [999999, Something unexpected caused the tool to fail. Failed to Execute (Update Schema)]" is returned when adding a new field to a related table from a hosted feature service in ArcGIS Pro.

Last Published: November 1, 2019 ArcGIS Pro
Bug ID Number BUG-000124062
SubmittedJuly 29, 2019
Last ModifiedOctober 14, 2020
Applies toArcGIS Pro
Version found2.4
Operating SystemWindows
Operating System Version10
Version Fixed2.5


  1. In ArcGIS Online, navigate to the item details page and the hosted feature service data.
  2. Add a new field to the related table.

Steps to Reproduce

Bug ID: BUG-000124062


  • ArcGIS Pro

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