Does SYNCING.NET store any data on the SYNCING.NET server?

Yes, but this primarily concerns configuration information of your SYNCING.NET user account and your SYNCING.NET "Sync Folders" and "Outlook Groups". Your Outlook data and your files are always stored locally on your computers. The data transfer between your computers is naturally cryptographically secured. Nobody can see the content of your files and data. 

If you are using the Store-and-Forward feature (accessible under SYNCING.NET “Configuration -> Options -> General Settings”), the cryptographically secured change requests from the last(!) computer online in your SYNCING.NET "Sync Folders" or "Outlook Groups" will be additionally copied onto our server and stored until another computer comes online alone and downloads the change requests from its so-called Store-and-Forward Inbox. In other words, this data is being stored locally on your computer and on our server.

Note:

• Only 500 MByte of change requests per computer (at a maximum of 50 MByte per file) can be stored
• After each computer has downloaded the change requests, they will be deleted immediately from the server
• If a given computer doesn't download the stored data within 7 days, the change requests in its Store-and-Forward Inbox will be deleted from our server and must then be transferred directly between the computers of your SYNCING.NET "Sync Folders" or "Outlook Groups". In order to do this the computers must be online at the same time as long as the transfer takes