I have the normal version form 1Password for Windows (version 188.8.131.525) and my vault is in folder in my PC.
I installed the 1Password Alpha version and when I assigned the vault, it says Bas vault format:
Why 1Password didn't recognize my vault?
1Password Version: Alpha 184.108.40.2060
Extension Version: Not Provided
OS Version: Windows 8.1
Sync Type: Local