Using N1MM Logger+ and ADIF Files to Merge Logs
This merge method is the most automated and should require no manual log editing, but will only succeed if the contest types in each logging computer were identical. If the contest types were not identical, it may be possible to recover with the help of a text editor and some detective work, but it will likely not be easy. It’s better by far to avoid this situation by using the identical contest types during the contest.

Examine the logs to ensure that the contest types are identical in each computer: >File >Open Log in Database
Export an ADIF file from each logging computer: >File >Export >Export ADIF to file. Assign a unique name to each ADIF file to distinguish it from others when importing. Before continuing, guarantee that the contest types from each computer were identical by opening each ADIF file with a text editor (like Notepad) and looking for the ADIF expression CONTEST_ID. They should all be the same length and contest name. For example: ❮CONTEST_ID:14❯ARRL-FIELD-DAY
Copy all exported ADIF files to the computer that will create the merged log
Launch N1MM Logger+ in the merge computer. If the merge computer is one of the ones that was used during the contest, you will need to create a new database for the merged log: >File >New Database. Now in the new database or on the new computer, create a new contest log for the merged records: >File >New Log in Database. Be careful to make the contest type identical to the contest type that was used during the contest
Import the extracted ADIF files one after another into the new contest log: >File >Import >Import ADIF from file
Use >Tools >Rescore Current Contest to rescore the contest
Extract the new, merged contest log for submission to the contest sponsor: >File >Generate Cabrillo File