No, not really - yet. We are working on true cloud-sync between multiple Windows devices. In the meantime you can do a 'hack' version by using the database restore feature on your other machines. Please note to only sync one machine to OneDrive, to ensure that is the master data. On you other machines, don't enable OneDrive sync within the app, but just regularly restore the database using the 'Restore from File' feature in the 'Backup/Restore' tab in Index Cards settings.