Click on Batch Mode

1. Navigate to your .txt list of MMSID numbers
2. Specify a destination file where the records will be saved (file name must end in .mrc)
3. Click Custom under Search Types and type @attr 1=12 (this specifies to search anywhere in the record)
4. Select Emory University (ALMA)
5. Click Retrieve Unicode box
6. Enter UTF8 as Server Character set (in some versions of MarcEdit, this option is not present)
7. Click green arrow at upper right to run

You get a report listing how many records were searched and how many were retrieved

And if records were not found from your search, there is a path to a .txt file that will show you what was not retrieved from OCLC.

Navigate to your .mrc file and double-click on it to break it with MarcEdit