QB Issue Resolution:
It is trying to use the Java to Cocoa bridge, which is something that Apple eliminated several years ago. I don’t think there is a work around unless there is a newer update to 2012 that had the registration rewritten (I know we did rewrite it, I don’t remember when).
You can try downloading a newer version of 2012 from here (if it is still available):
Resolution for Issue 'How can I register Quickbooks 2012 under Mac OS 10.11(El Capitan)?' available: Yes (Solved).
Source: Intuit Community forum.
How can I register Quickbooks 2012 under Mac OS 10.11(El Capitan)?: this issue or error code is a known issue in Quickbooks Online (QBO) and/or Quickbooks. Support for this issue is available either by self-service or paid support options. Experts are available to resolve your Quickbooks issue to ensure minimal downtime and continue running your business. First try to resolve the issue yourself by looking for a resolution described below. If it is a complex issue or you are unable to solve the issue, you may contact us by clicking here or by using other support options.Support for Apple eliminated several
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