This error message is received, when there is a bank account associated with one of the records. This account will need to be deleted before merging the records.

To find the bank account
  1. Search and select the record for one of the organizations you're trying to merge
  2. Navigate to the Revenue Tab, Click Accounts
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     3. Click the dropdown arrows next to any listed account, click delete
 
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  1. Once the bank accounts have been removed from the records, attempt to merge the records again.