not sure what you did; if you restore the database then you have the entire database, and if you import one entire database into another (to combine e.g. LCIA methods and ELCD) then you have the content of both databases combined.
Are you maybe using a newer Mac? There were quite some issues due to the new Java 9 on Macs which we solved with the 1.7 release (non-beta).
What does the error say?
- and maybe you should try 1.7 (non-beta)