Monitor Categories; may fail to update Monitor Categories in Account Type Rules and Workflows

Monitor Categories may fail to update when running an Account Type Rule or Workflow Item and return an error including the following text "Failed to update Account Monitor Category. Account Monitor Category A/B/C is not configured for use".

This occurs if an Account Type Rule or Workflow Type item is defined that updates a Monitor Category and then that Monitor Category is later disabled.

Steps to recreate:

1. Go to Tools, Global Settings, Accounts, General and check "Use" for Monitor Categories A, B and C.
2. Set up an Account Type Rule or Workflow Type to update Monitor Category C.
3. Go back to Tools, Global Settings, Accounts, General and uncheck "Use" Monitor Category C.
4. Add a new Account or Workflow that triggers the Rule or Workflow defined in step 2.