cannot read the usb drive

Discussion in 'MacBook Pro' started by gary_chen_1379, Apr 15, 2017.

  1. gary_chen_1379 macrumors newbie

    Apr 10, 2017
    Hey guys,

    I'm using the MacBook Pro 15-inch late 2016 for about three month. The version of the operating system I'm currently on is macOS Sierra 10.12.4. Recently, I use the Apple USB-C to USB-A adapter to connect my hard drive disk (Seagate Back Up Plus Slim 2Tb for Mac). Everything just went okay. However, when I use the same Apple adapter (USB-C to USB-A) to connect the usb flash drive (HP v250w, format: FAT32), I found out that my MacBook Pro "cannot" even read it! It just didn't show up in Finder Sidebar , desktop, or even in Disk Utility. No matter what I've done such as rebooting, restoring SMC, this problem just cannot be solved. (I am sure that the usb flash drive is working because I can read it with my windows 8 computer)

    Am I the only one who has this problem? Please help me! Thanks a lot!
  2. Sanpete macrumors 68020

    Nov 17, 2016
  3. gary_chen_1379 thread starter macrumors newbie

    Apr 10, 2017
    Yes, it can also work well with the usb-ethernet adapter, etc. Somehow it just cannot work with usb flash drive.
  4. MC6800 macrumors 6502

    Jun 29, 2016
    The HP v250w is known to not work right (or at all) with Macs. Try another model or brand.
  5. Oldteker macrumors newbie


    Dec 7, 2017
    I am having the same problem with MacOS 10.13.2 on some of my USB flash drives.
    These same drives work fine on 10.13.1.
  6. New_Mac_Smell macrumors 68000


    Oct 17, 2016
    This may be the same thing as something that's happened on Macs for year, so worth a check.

    Basically things can get a little screwy between Windows and MacOS if ever they are disconnected without ejecting, at least I find. If you do have this problem, open up Activity Monitor, there's a process in there you may see that I cannot remember the exact name of, but it relates to the disk. Something like CHDisk, Spindump, someone will know the exact one.

    Anyway, force kill that process and it should start to read it. It may come up asking for a repair so just go through that. What I think happens is it tries to mount it and then repair, and something in the way it was ejected from Windows causes this to hang. So it won't show up as even connected in Disk Utility and can be frustrating. But this force kill always works for me.
  7. Oldteker macrumors newbie


    Dec 7, 2017
    Thank you for the suggestion.
    This has nothing to do with Windows vs MacOS.
    It appears to be a problem with MacOS 10.13.2 vs 10.13.1.
    It turns out that the same problem exists with MOS 10.13.2 reading MicroSD flash cards, as well.

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