I'm dealing with a similar issue. Were you previously using Quick Charge? Regardless, I've tested multiple cords, different PCs, and ran ALL of the normal troubleshooting ofr fixing ActievSync issues. Basically, the device stopped charging in the car...then when I docked it, ActiveSync wouldn't recognize it. I put the phone into bootloader and it will not switch from "serial" to "usb", so the only way to flash is via storage card, which works fine.

The device will only charge if connected using the HTC charger or connected to the PC.

I've read warnings of Quick Charge potentially damaging the USB, so I assumed that was the cause of the issue.

I'm going to relock and take in for repair. I even flashed Stock thinking it could be a driver issue, but nothing seems to do it. I'm feeling your pain, dude.

I'd recommend relocking. You'll want to get a card reader for your PC if you go this route, otherwise it's a bit of a pain to download everything to the device. There's a thread here with everything you need.

Good luck!