Insert error during company code change. Process terminated.

What causes this issue?

A write error has occurred on the database while marking persons being
assigned to a new company code, or due to a manual trigger. Check table
T77INT to see if the persons have been updated there.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Error message extract from SAP system. Copyright SAP SE.