1P4 and 1P3 through Dropbox?

Update: I saw a hint about starting over and choosing the "Already a 1Password user" option. I tried that a couple different ways, and chose the Work.agilekeychain vault in Dropbox, but that got an error. When choosing the Dropbox option, there is no opportunity to choose a file, it always creates the 1Password.agilekeychain file.

So... as a workaround, in the Dropbox folder, I renamed 1Password.agilekeychain to _OLD. and created a symbolic link named 1Password.agilekeychain that points to Work.agilekeychain. This is successfully syncing bidirectionally, so apparently the file format is compatible between 3 and 4. I imagine this method is not supported, but it's working for now. I'd still like to find out if there is a standard way to do this.

1P4 is the one that set the names on my Vault files. I'm trying to get 1P3 to recognize one of those as its "primary" vault. There are other posts here about sharing secondary vaults with other 1P systems, and I'm looking to see if there is a standard or normal way to tell 1P3 to initially start up with a known file name in Dropbox instead of trying to establish a new one.

I found a nice document "How to share a non-primary vault" which documents all the steps for sharing a vault through Dropbox shared folders instead of what I was trying to do. I tore down what I had set up and went through all the steps. It all worked fine up to the step "Nik first needs to unlock his main 1Password app. Once unlocked, all Nik has to do is open the shared folder and double-click the shared vault.... When he does, 1Password will prompt him to create a new vault on his end. He’ll need to provide the password I selected when I created the vault on my end."

Maybe because the recipient is 1P3 which does not understand vaults, it only prompts to Merge or Replace data. The shared data gets merged in on a one-time basis. I don't see any way to switch 1P3 to use the shared folder for its data. The "Your Data Stored In" field seems immutable... changing to Dropbox wants to create a new 1Password.agilekeychain in Dropbox. Is there any way to "adopt" that shared keychain in 1P3?

The right-click method does indeed load the data, with a choice of Replace or Merge. But it does not make that file the active data file.

1Password will now use that keychain to sync all changes to (you can confirm this in Preferences > Sync, if you'd like.)

That's the part that does not happen. In 1P3 Preferences, there is no Sync tab. "Your Data Stored In" is on the General tab, and points to ~Library > Containers > com... > Data > Documents > 1Password.agilekeychain. Pressing "Use Dropbox..." just pushes the 1Password.agilekeychain to Dropbox, it never makes a connection to the Work... file that should remain sync'd.

This is 1Password for Mac 3.9.6 (39600.038) on Mountain Lion.

I have just sent the report.

I can't seem to locate the email thread, so here's my follow-up. As recommended, I updated my work mac to Mountain Lion 10.8.5. I uninstalled 1P3 and installed 1P4 from the App Store. I was able to navigate to my work-specific Dropbox file and 1P4 imported it very nicely. It seems to be syncing properly in both directions, though I noticed two quirks:

1. The files in Dropbox as shown on the Mac do not get their date/time stamps updated, though the top-level Dropbox directory does. That made me think for a while that it wasn't syncing. That's not your issue, but I thought it might be useful info.
2. There's a bit of a delay in the Mac importing changes from Dropbox, but not too bad. Is there a way to force a sync? I did not find one.

So far so good - looks like it's working. Thank you very much for your help!