Using the Rebuild Address Locator tool with locators that are part of a composite locator fails with the error 999999.

Additional Information

Workaround

From documentation, the workarounds for rebuilding address locators are to either:

• Re-create each of the participating locators with the Create Locator or Create Feature Locator tool by rerunning the tool from the History pane, ModelBuilder model, or Python script.
• Remove the locators from the project to avoid a schema lock error, add the locators with the updated data to the Rebuild Address Locator tool, and run the tool.

Keep your locator up to date—ArcGIS Pro | Documentation 

Steps to Reproduce