It's an old external usb driver in NTFS that was working fine with my windows 7, and later I formatted it into ExFat by my MBP that I hoped it could be consumed by both PC and Mac. Unfortunately the Windows 7 could NOT find it any more (while works perfect with my Mac). The USB drive is visible in Windows 7's device manager (good status, running), but NOT in file explorer (my computer) or disk management (therefore I have no way to format it by Windows).
Anyone could help? Thanks a lot.