This will be a quick post on an error I had when setting up a fresh AX2012 R3 installation. I was getting a bit ahead of myself and got stuck with an error when synchronizing the database.
And to help search engines find this post, the error in clear text:
Cannot create a record in Inheritance relation (SysInheritanceRelations). MainTableId: 12345.
The record already exists.
The error is due to the fact that I didn't restart the AOS after compiling the application. Lesson is; don't rush and do it the right way the first time.
Furthermore, if you DO get stuck, try do a quick search on Life Cycle Services for a solution:
Restarted the AOS and continued the installation.