Serato locking up, ideas?

Windows 10 with latest updates
Serato Pro 2.4.3
DDJ-FLX6 controller

Prior I was running Serato 2.1 with a Roland DJ-202 and it worked perfectly. I uninstalled Serato and put the new version on. When I plug the FLX6 in, it locks up every time I'm playing a song. If I unplug the controller after a second it starts playing in PC mode thru my sound bar. And if I reattach the USB it starts working again, but depending on how much longer the track has it might lock up again. If I load another song 99% it locks up, a few times I've gotten it to play an entire song without the freezing, but when I loaded the next song same problem. When I quit Serato if the controller's plugged in I have to unplug it or Serato will sit there and not respond. I installed RB, and that works flawlessly, but I'd really rather use Serato so I'm seeing if anyone has a suggestion. Here's what I've tried already.

totally removed Serato, even the stuff it leaves behind in the user/appdata folder.
tried a different USB port
set the USB buffer size to max in Serato

I can't try the Serato 2.1 I have as FLX6 support was just added to 2.4.3

I emailed Serato support 5 days ago, they had me send the results from DXDIAG, but I still haven't heard back from them. I'm wondering if maybe someone here has an idea. Someone elsewhere told me to try a different USB cable, but I don't have one at the moment. Plus the one I have RB's working perfect so I can't see how it could be the cable.

If anyone actually replies, I hooked up a spare SSD and did a fresh install of Windows 10. With nothing but Windows and Serato 2.4.3 installed it still freezes every song. I also tried another USB cable and a 3rd USB port. I guess this version of Serato has problems with some hardware in my system. If anyone has an idea I'm still listening. Probably going to save up and buy a laptop, that would have to fix whatever the problem is, I'm assuming if I return the controller and get a 1000SRT the same sh*t would happen on this computer. I need to fix the Serato + computer problem before I think about a different controller.