I'm having the same issue on my new computer, I am completely unable to sync music to my Samsung Galaxy S7's SD Card. It syncs the first song and the rest is "Copy Failed - Exception from HRESULT: 0x802A0006". I cleared my temporary files and made sure to have my phone unlocked the whole time.
I have the Windows Store version 3.3.7165.
If anybody could help me on this, it's very frustrating, thank you!