2 Replies Latest reply: Oct 29, 2010 7:11 PM by Follower
Follower Level 1 Level 1 (0 points)
A long-time Mac user client of mine bought a Mac Mini in August, It ran faultlessly until early in October when it began to freeze, most frequently when Time Machine was doing its thing with an external, USB-connected, hard drive.

Ten days I took it to an Apple dealer who ran the extended Mac Mini test suite without any hiccups. Returned from dealer and the Mini still froze, usually (always?) with USB activity.

Dealer replaced the HD and I retrieved the Time Machine backup, giving it back to the owner on Oct. 23.

No freezing for the first four days, but on Wednesday I got this message from the owner:

"Unfortunately I have to report that my computer froze on me again a few
minutes ago. I was opening (or trying to open) a Word document while the
backup was going on ... Maybe that's the problem?

I saw white streaks on the screen, and then the **** thing froze ..."

This morning (Friday) he tells me that the memory stick he also uses as a backup and to move files to an old iBook has been corrupted by the Mac mini: not readable by an original mac mini, the iBook or the new Mac Mini.

As it's a 120-mile round-trip for me, some suggestions as to where I should go from here would be welcome. One thing I am doing is taking a FireWire cable with me to connect the external Time Machine drive to see whether it really is a USB problem.

2010 MacMini, Mac OS X (10.6.4), 2gb of RAM, using HDMI to HDMI-equipped monitor
  • Boece Level 5 Level 5 (6,245 points)
    Is this a new Aluminum Mini?

    Is everything running on a UPS, so that you can rule out power issues?

    The white streaks on the screen suggest a RAM issue to me. Has the factory RAM been upgraded to something else?

    What brand of external drive is being used for Time Machine? (There are several critics of WD bookshelf drives in this forum.)

    Does the drive use usb power or have its own supply?

    Is a USB hub being used?

    I would be extra careful to check the quality of any usb cables or usb extension cords being used. I have had Mini weirdness clear up just by swapping usb cords.

    (Probably worth visiting monoprice.com and ordering up a complete set of good usb cables for troubleshooting in all shapes and lengths. Would set you back about as much as buying one or two usb cables at an office store.)

    I've observed that Time Machine doesn't behave very well if drives spin down. You might check to be sure the external is spinning up in time.

    Have you considered running tests in your own workplace?

    Was there a change in hardware or software configuration in early October, when this trouble started?
  • Follower Level 1 Level 1 (0 points)
    Thank you, Boece, for your thoughtful comments and suggestions.

    Briefly, yes it's a new aluminum mini with only Apple installed RAM without a UPS. The backup drive is a Seagate 3.5" in a generic, powered, enclosure with both USB2 and Firewire capabilities. The enclosure does not allow the drive to spin down. A hub is used, but only to connect a printer and, very occasionally a digital camera. Hadn't thought about USB cables, but might give that a shot. The client also uses a USB-based wireless keyboard and mouse. As for changes coinciding with the onset of the problems, nothing other than whatever Snow Leopard updates there were at the time.

    After creating this morning's original post, I took a cable to the client's house and attached the external drive using firewire. I also detached the wireless keyboard and mouse's USB transmitter, substituting just a regular Apple keyboard and mouse. After a re-boot I ran the Time Machine backup without any signs of freezing, and I got report tonight saying that the computer is back running without issues and that Time Machine has worked without any glitches.

    While I'm not at all confident that the problems have gone away, it does seem to point to a USB-related issue, but whether that's at the board level or at the cable/device level is yet to be determined.