External HDD eventual hang / "in use" issue

Discussion in 'Mac Accessories' started by doobydoooby, Mar 19, 2015.

  1. doobydoooby macrumors member


    Oct 17, 2011
    Genève, Switzerland

    I'm experiencing a weird issue with an external usb 3 hdd attached to my mac pro 3.1 - it works absolutely fine for a day or two and then I suddenly notice that it is "kinda" locked up. There are no error messages, the drive is still mounted and i can view the file structure in Finder but if I try to write to the drive it completes instantly without having actually written anything. It happens very consistently if the mac is on for a day or two.

    The only way to make the drive work again is by unmounting and remounting it, and this is the only clue that I have to my problem - when i try to unmount the disk Finder says that it isnt possible to unmount because the disk is in use. So I have to force unmount it.

    My question is, has anyone else had a similar experience and / or does anyone know how I can find out if a process on my mac is genuinely keeping the disk in use? Since its happening when I'm not accessing the disk actively I'm wondering if it has something to do with a background process I'm not aware of (eg) time machine although time machine is not backing up this drive. I just would like to find a way in console of seeing what is actually keeping it from relaxing.

    Any response gratefully received...
  2. ColdCase macrumors 68030

    Feb 10, 2008
    I find the recent finders to be quirky. Have you updated the OS recently?

    It may be the finder holding the drive at bay. If you force quit (relaunch) the finder, does function return to normal?

    It may just be one of those USB things, a marginally bad cable, port, connection, a enclosure, or a bad drive.

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