Workflow [guid] does not exist when importing a solution.

Trying to import an unmanaged solution into a Microsoft Dynamics CRM 2015 On Premise instance.  I received the message Workflow {5125476c-7889-e611-8177-0050569c5846} does not exist, processtrigger With Id = 5925476c-7889-e611-8177-0050569c5846 Does Not Exist.

After hunting for a workflow rule that didn’t exist for a while, I discovered CRM classifies Workflows as Business Rules

When is a workflow not a workflow? When it's a Business Rule

I changed the scope of the Business Rule from a single form to “All Forms” as defined in https://community.dynamics.com/crm/f/117/t/239472 which resolved the issue.