As DEVONthink cannot (yet) open multiple databases at a time, there can be the necessity to combine two databases. Here’s Bill DeVille’s quick guide to combining databases:

1. Assume the contents of databases A and B are to be merged into database C. In the Finder, create two new empty folders, named A and B, which will be used to hold the contents of their corresponding databases.
2. In DEVONthink Pro, open database A. Select all of the contents of the database. Choose File > Export > Files & Folders, and choose folder A as the target.
3. Do the same for database B.
4. In database C, select File > Import > Files & Folders. Choose the content of folder A. Repeat, choosing the content of folder B.

Now the three databases have been combined. DEVONthink Pro uses “DEVONtech_Storage” files to keep meta data during export/import.