I have multiple devices with codebook and read how to change it:
Did the following:
1 - Synced all my devices.
2 - Changed my Windows 10 Codebook password with the “Change Password” option.
3 - Selected “Overwrite Dropbox” under Sync menu.
4 - Gets about 30% through and gets ‘Invalid Password’ message.
I read here how to do this so I am doing something wrong or missing a step.