[Material Sync not working]

Having the exact same problem. Syncing from Cura just sits there and spins. I can see traffic via my router going to/from the printer, but it still keeps spinning the syncing icon. Not sure what to expect at this point.

 

All I was really trying to do is sync a customized material profile that matches the 3DXTech CarbonX PETG+CF profile from the marketplace. I'm not using that one (not even installed) because it doesn't support the CC 0.4 nozzle (even though 3DXTech website says it's viable as a nozzle diameter). 

 

And, following the USB method says there's no new material profiles...

[MakerBot and Ultimaker agree to merge]

Anything at all that can make the MakerBot software more standards-centric (and open source) will be an astounding success. I [briefly] owned a MakerBot Method X Carbon Fiber and spend two weeks trying to get it to print reliability. I ended up returning it and getting an Ultimaker S5 and haven't looked back. To be fair, there was a lot of tech goodness going for the Method X, but at the end of the day it was poor [proprietary] slicing software and terrible support that made me send it back within the 30-day return window. I'm willing to bet if CURA had been usable on the Method X I would still have that device today.

 

I just hope this merger doesn't degrade all the good I've seen with Ultimaker hardware and CURA software so far or obsolete this still newish S5.

 

[Need help with installing materials]

I'm seeing the exact same thing. Installed Polymaker PolySmooth (PVB) via the Marketplace, restarted Cura, and still the only thing that shows under Polymaker is PLA.