This issue occurs when the user does not have the Run Flows permission in Salesforce. In Lightning, Apsona List View merge buttons rely on Salesforce Flows to process multiple selected records. If the user lacks permission to run flows, Salesforce blocks the process and displays an “insufficient privileges” error.
This issue is specific to List View merges. Single-record merge buttons may continue to work normally because they do not depend on the same flow-based mechanism.
To resolve the issue, grant the user the Run Flows system permission through their profile or a permission set. If needed, also verify that the user has access to the Apsona List View Merge Flow.
Once the Run Flows permission is enabled, the user can successfully run List View merge buttons in Lightning. If a merge works for a single record but fails from a List View, checking the Run Flows permission should be the first troubleshooting step.