Using the Windows 7 File/Open Data Folder to open a open a secondary vault synced to dropbox from a Mac, it seems to prompt correctly for a password, but then when I type in the password I get an error message
1Password has encountered a problem
Unable to unlock 1Password Data.
Your 1Password Data could not be unlocked with the password you provided. Please verify the password and try again.
I have just installed both versions and checked for the most recent updates. I triple checked the password on my Mac, and it works fine, assuming of course that the password isn't somehow different from the master password. I can use the same password on Windows to switch back into the primary vault on dropbox.