Popular "cloud-sync" tools such as Google Drive, Google Backup & Sync, Google Drive File Stream, Microsoft OneDrive, DropBox and many others allow synchronisation of files between multiple devices.
However, file synchronisation is not the same as file sharing. Probate Plus is a database application and uses constant and random read/write access to database files held in the central data folder. A cloud-sync service will most likely interfere with such operations.
In the best case, files get locked and only one user can access them. In worst cases, data can get overwritten and/or corrupted or lost as the sync service tries to update files. A sync service is designed for use with typical files (word documents, photos etc) and not database files.
We do not recommend placing Probate Plus database files in a folder that is synchronised by a cloud service. There should be a single data folder shared via an operating system. If distributed / multi branch / home working access is required then connection back to the central data folder over VPN or sharing of the Probate Plus application using terminal services are recommended methods and the client-server add-on for Probate Plus will likely be required.
It should be noted that cloud storage is a good backup storage media, and as long as the files are not directly used, you can use cloud storage for a backup. You could use the cloud storage to hold a copy of the "live" Probate Plus data folder after you have completed working on it.
More detailed IT-level information:
"[The Probate Plus database engine] opens the database files deny read\write and caches index pages. It also does not expect the files to be changed by an outside application with proprietary locking. If you are using compatibility locking with DBFs, certain byte offsets in files need to be locked to prevent data corruption from race conditions between Probate Plus and other programs. A cloud sync service will not lock those bytes before making an update."