Official comment
Roman,
The list of platforms that are supported and tested with each Syncplicity release is kept here:
https://syncplicity.zendesk.com/hc/en-us/articles/201569954
Vista is not supported, although the Windows client likely works on that platform in you have current .NET installed. However, we cannot guarantee Vista compatibility.
You manage the devices in your account, including deleting them if you need to, in the web interface at my.syncplicity.com. Follow the steps in this article to get to the device management page: