How to set up cloud syncing for Password Agent

First we must realize that there is no easy and foolproof way to have your data synced between Windows and mobile devices, as Password Agent stores data in disk files and these must be copied from one place to another and back, and since the files are encrypted they cannot be easily merged automatically on file conflicts etc. So if you still want to sync then you must take into account the following points.

To sync Password Agent data files from Windows computer to cloud storage you need 3rd party “cloud software” like Google Drive, Microsoft OneDrive etc. Here we discuss how to set up such configuration and what to take into account, so you do not to lose your data when syncing.
Cloud software can update local file from cloud only when the local file is not currently in use by Password Agent. In-use means the file is unlocked with master password. By default Password Agent locks all open/unlocked files after 10 minutes of inactivity, but you may have changed that behavior by program settings. You should set setting “User inactivity action” to “Lock open files” (or “Lock open files and minimize”) and “User inactivity timeout” to some reasonable value, like 10 or less minutes. When you know you have modified your cloud file on mobile device and the file is also open in Password Agent in Windows, then lock the file in Windows so next time you unlock it, it is (hopefully) up to date. Last modified time tells when it was last updated, to give you some glue. Also, if you want to update your data mostly from mobile device and often, then you can also open files in Windows version read-only. Files opened in read-only mode will be writable for cloud software all the time. You can select “Open read-only” checkbox on unlock screen of a file or change program setting to have it selected by default, so you can opt out if needed.
When saving data file Windows version keeps previous version of the data file as a backup, but renames it to have extension .oldN (where N is a number). By default 5 older versions are kept, just in case you need to revert to older data file. So each time you modify a file, all these 5 old versions also change name, which means total 6 files need to be transferred back to cloud by cloud software each time you make a single modification to your file. If your files are large (contain attachments) and connection is limited, then the process may become slow. If that is the case you can reduce the number of old files to keep (see Settings/Backup) so there is less old files to copy with each file update.
The most foolproof way to setup sync between multiple devices is one way syncing. You always update data file on certain “master” device only and updated file is saved or copied to cloud, where other devices can access always latest version of the file.