BBB can't connect to laptop through USB port with the existence of SD card

After update Angstrong in eMMC by SD card, I restart BBB with and without SD card. Everything is fine without SD card and I can access to it through ssh in linux console. But if I leave SD card on the board and just boot up from eMMC, after log in as root, BBB would try to connect USB port but can’t finish it and so I can’t connect to it as I’ve done without SD card.
Anyone has met the same thing?

I haven’t been able to ever connect through USB, but I’ve always had the SD card in.