Choosing to use the data file from Dropbox won't erase your
previous data, but it will tell 1Password to use your data file in
Dropbox, the old data file will still be available but you can only
have one data file open within 1Password at a time.
What I would suggest, before you go any further, is to not use
the new data file and go to File > Backup on the MacBook Pro so
that you have a backup of your current data.
That said, although we don't currently have an automatic way to
merge two data files, this isn't hard to do using a manual process
and so I'll do my best to walk you through that now.
First of all, you need to decide which of your two Macs will be
the 'master' for creating this new data file, be it your MacBook or
MacBook Pro, and once you've done this please make sure the data
file for this system is stored in Dropbox.
Then on the other Mac make sure that you're using the original
data file, or rather don't sync it with Dropbox.
The next step is to export the data from your secondary Mac so
you can import this to your 'master' Mac to create this new data
file for syncing. To do this you can either use the File >
Export All or File > Export Selected options and select
'1Password Interchange File' as the export format.
The option you chose depends on if you want to export all of the
data from the secondary system and deal with any duplicates after
import, or just export the information that you know isn't on the
If you save this file to your Dropbox, and then open 1Password
on the 'master' Mac and go to File > Import and select
'1Password Interchange File' from the 'Import Format' drop-down
menu and then follow the steps to import your data. Once the import
is complete, please drag the .1pif file to the trash and then use
the Finder > Secure Empty Trash option, as these exports aren't
After you're happy with the new data file on your 'master' Mac,
and both Macs see a green check on the '1Paassword.agilekeychain'
file in Dropbox, you can then tell the secondary Mac to use this
new data file by simply double-clicking the file in Dropbox.
Great, what I'd suggest is to move the 1Password.agilekeychain
file on the MacBook to somewhere else for now, even your desktop,
double-click the file to tell 1Password to use it and then follow
the rest of the steps above, you don't really want either Mac using
Dropbox while you're exporting and importing data.