Merges the selected mailboxes (or .eml files) into a single mailbox file with the name and location of the oldest mailbox (or .eml file) in the selection. The tags and notes of the messages are preserved. (Source URLs of the mailboxes and custom titles and from names of message files, in the unlikely event that there are any, are not.) The original files are then moved to the trash.
Merging can reduce clutter in the source list and speed up EagleFiler. For more information about mailbox files and message files, see the Importing Mail section.
Apple Mail .emlx Files
Although it can search and display them, EagleFiler cannot directly merge .emlx files, and it is generally not recommended to use .emlx files because there can be multiple files per message that may get separated. If you follow the instructions in the Importing Mail From Apple Mail section, you can ensure that EagleFiler imports mail using either the .eml or mbox format, both of which are standard formats, and both of which support merging.
Folders
EagleFiler cannot directly merge a folder and a mailbox. You would need to select the .eml files within the folder, along with the mailbox, in the records list. If this is inconvenient, you can do it in two steps: first merge the messages to create a new mailbox and then select the two mailboxes to merge. Or you can tag the various messages and mailboxes that you want to merge, then select everything within that tag and choose Merge Mailboxes.