[Apologies for raising in incorrect category - ll the others were greyed out!]
My vault was not syncing correctly between Windows and iOS using Dropbox. Following instructions to force it to sync I renamed the vault file. This has created a new vault file with a different name but has reverted to an old version before I had changed a substantial number of the passwords. I can see the file in DropBox for the second vault but it only contains the data file and nothing else. When I try to open it gives an error message saying it is not a 1Password vault and "Dropbox is probably busy syncing your 1Password vault. Please wait" This was several days ago however.
1Password Version: 126.96.36.1996
Extension Version: 188.8.131.52
OS Version: 6.2.9200
Sync Type: Dropbox
Referrer: forum-search:unable to open duplicated vault