Can't add both nsf archive files

I have two .nsf archive files, archive1.nsf and archive2.nsf. I go into Tools > Options > Indexing > Email > Lotus Notes
and click on "Select Databases and Folders To Scan..."
I can pick archive1 and all is good. But when I pick archive2 it's there, but archive1 is gone. I go back and pick archive1 and then archive2 is gone.

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