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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
    10,858
    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.
    "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
    Keller, Texas
    Posts
    50,261
    Specs:
    Late 2013 27" iMac, iPad 3, iPhone 6s+, iPhone 6+, 3 iPods, Sierra
    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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