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  1. #1


    Member Since
    Mar 09, 2012
    Location
    Manchester, MI
    Posts
    6
    Specs:
    iMac 21.5" 2.5Ghz Intel Core i5 4GB RAM
    Time Machine Won't Backup
    I have been trying to back up my iMac 21.5inch - Mid 2011 (running Lion 10.7.5) using Time Machine. The backup target disk is a Seagate "Backup Plus For Mac" 500GB external drive, connected with a USB 3.0 cable.

    Every time I have tried to back up, Time Machine will run for a few minutes and stop with a message that the "disk has been improperly disconnected". Then my iMac freezes and I have to do a hard reboot.

    The disk was not disconnected at any time during the backup. The Seagate disk checks out as fine. I have tried reformatting the disk with not results.

    Any suggestions as to what might be going wrong?

  2. #2

    Slydude's Avatar
    Member Since
    Nov 16, 2009
    Location
    North Louisiana, USA
    Posts
    9,239
    Specs:
    2.8 GHz MacBook Pro 10.11, 8 GB mem, iPhone 6+
    I did a little digging about this with the help of the great Google monster and have not found anything specific yet. I did find out that some models of this drive ship with a piece of Paragon software to make it useful for Mac and PC. That is making me wonder how your drive is formatted. Here is what I would try:

    With the drive connected and mounted in the Finder press Command I to bring up the Get Info window. If the drive will be used with Time Machine it must be formatted HFS+ extended, journaled. If the drive needs to be formatted you can do that from Disk Utility.

    BTW is this drive powered from the USB port or does it have a separate power cord. The error you are getting sounds suspiciously like the drive is formatted correctly but not getting enough power. This sometimes happens with US bus-powered drives that must be connected to two ports.
    Sylvester Roque Former Contributing Editor About This Particular Macintosh

    "Got Time to breathe. You got time for music." Denver Pyle as Briscoe Darling

  3. #3

    chscag's Avatar
    Member Since
    Jan 23, 2008
    Location
    Fort Worth, Texas
    Posts
    47,121
    Specs:
    27" iMac i5, 3.2 GHz, iPad 3, iPhone 5c, iPhone 6+, 3 iPods, El Capitan
    The backup target disk is a Seagate "Backup Plus For Mac" 500GB external drive, connected with a USB 3.0 cable.
    Just a thought here..... since your 21.5" 2011 iMac does not support USB 3.0 drives as USB 3.0, that may be the problem. I know that USB 3.0 drives are supposed to be backward compatible with USB 2.0. Sometimes, they're not. I'm basing that on personal experience. I have the same exact machine you have and had to return a USB 3.0 drive to Best Buy because it did not work right with my iMac.

  4. #4


    Member Since
    Mar 09, 2012
    Location
    Manchester, MI
    Posts
    6
    Specs:
    iMac 21.5" 2.5Ghz Intel Core i5 4GB RAM
    thank you
    Thanks for the assistance, Slydude and chscag!

    This drive is powered by the USB connector. Since I have already reformatted the drive as indicated, the power cord may be the issue.

    I don't think I will be able to return it to Best Buy, so I guess I just have another external drive for movie and music.

    Is there another drive that either of you would recommend?

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