Hi @estebanperalta54 

This is a common error. If you have 2 people in the same screen, it will occur or if you have 2 tabs open for this screen. 

Try to get the users out of that screen and log out. 

Clearing the cache may help also. 

Also, here are some steps you can take in that:

https://community.acumatica.com/maintenance-and-troubleshooting-229/how-to-resolve-the-another-process-has-added-the-entity-record-your-changes-will-be-lost-error-on-a-user-s-attempt-to-change-a-record-id-237

Thanks for your answer @kandybeatty49. The suggested solutions did not work, instead I had to escalate a case with Acumatica. They were able to apply a script and fix it. This is what they mentioned:

In previous versions, the issue is caused when a branch is deleted and a new one is created with the same name. This should have been fixed, we will be investigating the root cause further. A correction script has been applied and you should be able to create interbranch account mapping.

Thank you for sharing your solution with the community @estebanperalta54!