Since Sierra upgrade, can't write to backup drives

Discussion in 'macOS Sierra (10.12)' started by bennyprofane42, Dec 7, 2016.

  1. bennyprofane42 macrumors newbie

    Jun 2, 2016
    I have a few external USB drives I use for running backups with my MacBook (in addition to Time Machine). Since upgrading to Sierra, my permissions have changed: I can no longer write to them, just read them. They are NOT NTFS-formatted, so that's not the issue (and again, I'd been writing to them for more than a year, no problem). I can read and write fine from my PC, so it's not a disc problem, it's clearly something with how the OS is changing permissions.

    How can I change permissions back so I can use these backup drives?

    Funnily enough--and fortunately, considering how often Macs seem to die--my Time Machine drive is still working great.

    It's a 13" Macbook Pro running, yes, Sierra.
  2. pauljbax macrumors member


    Apr 16, 2005
  3. FreakinEurekan macrumors 68040


    Sep 8, 2011
    Eureka Springs, Arkansas
    What format are they?

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