I have Trimble Link and Trimble Office sync on my computer. When I try to download a file to SCS900, I get a message that no sync program is availible and cannot go any further.
To be able to communicate with SCS900, you will need the actual software. Visit the website and obtain the software. I recommend you to do this because the software package also contains the drivers needed to connect the devices and the software. This could be the main cause of your issue.