Storing vault on USB stick

@Mattruss1 Thanks for the question! In 1Password for Mac, sync is a sort of three-legged affair in most cases. 1Password for Mac itself uses a sqlite database internally for your data. That's the first "leg." You can see it located at either:

• ~/Library/Application Support/1Password 4/Data/OnePassword.sqlite (if you downloaded your copy of 1Password from us), or
• ~/Library/Containers/2BUA8C4S2C.com.agilebits.onepassword-osx-helper/Data/Library/Data/OnePassword.sqlite (if you purchased from the Mac App Store)

In either case, everything's (obviously) encrypted, but that's what you're seeing when you open 1Password for Mac with your Master Password. If you never sync your data using any of the methods in Preferences > Sync, this is where your data resides.

When you do choose to sync it, if you select either Dropbox or Folder Sync as your sync method, 1Password will write out an OPVault keychain that will look like 1password.opvault (the name can vary but the file type will always be .opvault). This is the second "leg," and if you chose Folder sync, it's the last leg: 1Password's internal sqlite is syncing with this keychain on a local disk in a location of your choice.

If you chose Dropbox as your sync method, 1Password will put this sync keychain in your Dropbox folder, and we rely on the Dropbox sync engine to perform its magic and sync that OPVault with their servers, so that the reverse can happen on all other devices you link up to this Dropbox account and other instances of 1Password that use the same keychain. That's the third "leg" of the sync equation, in the case of Dropbox sync: Internal sqlite database syncs with OPVault keychain, which then syncs with the remote version of itself on Dropbox's servers (and then out again to various other devices).

This does allow advanced users to locate their OPVault sync keychain on a USB flash drive, for example, instead of in their Dropbox folder. Syncing to a USB flash drive is certainly possible, but it won't keep 1Password from showing data when you remove the flash drive, only from syncing. There's no way to do what I think you're asking, which is have 1Password's data ONLY on the USB flash drive and nowhere else.