5 Replies Latest reply: Sep 30, 2013 11:37 PM by nbar
pamela used to love apple Level 1 Level 1 (0 points)

I am running Snow Leopard on Mac Book Pro laptop.  I have external HD connected via USB that powers to an outlet.  I have Time Machine turned on and directed to use the external HD.  However, the only way it performs a back up is if I tell it to Back Up Now or go to Select Disk and choose the external HD.  If I let the computer just sit, the automatic back ups do not occur.  I do not get any messages that the last back up was delayed.  It just indicates when the last back up was and when the next one will occur, though it does NOT occur unless I do the steps above.  It simply skips the back up and then states a new time for the next back up, which, of course, does not occur.  Is this happening because the computer goes to sleep?  Doesn't Time Machine know to wake it to preform the back up?  It seems odd that I would have to keep my computer awake all the time just so it can preform automatic back ups.


MacBook Pro
  • Pondini Level 8 Level 8 (38,720 points)

    Hi, again!

     

    Sounds like the preferences file is damaged.  Try a "full reset," per #A4 in Time Machine - Troubleshooting.

     

    Your Mac won't wake just to do a backup (some recent ones, running Mountain Lion, can).  But if you have Wake for network access checked in System Preferences > Energy Saver, it should wake periodically and, if a backup is due, run one.

  • pamela used to love apple Level 1 Level 1 (0 points)

    Hi ya Pondini !!!

     

    Just when you thought you were rid of me......... 

     

    Deleting something inside of /Library/Preferences ?  That sounds scary.  I read Time Machine - Troubleshooting #A4.  When you disconnect and power off external HD and then reconnect it (step 4), do I power it back up again before deletig plist or just connect it?

     

    I'm wondering if my Mac Book is not doing a backup because there are no changes that were made since the last back up.  Could this be the reason?

     

    Thanks AGAIN!!

  • Pondini Level 8 Level 8 (38,720 points)

    pamela used to love apple wrote:

    . . .

    Deleting something inside of /Library/Preferences ?  That sounds scary. 

    Naw.  It gets damaged now and then. 

     

    do I power it back up again before deletig plist or just connect it?

    Doesn't matter.

     

    I'm wondering if my Mac Book is not doing a backup because there are no changes that were made since the last back up.  Could this be the reason?

    Nope.  It has to run to see what to do.  And there's always something changed, even if only a few system files (your Mac is always doing all sorts of things "in the background" for you).  And the plist itself gets updated with the status after each backup, so it needs to be backed-up, too.

  • kcargill Level 1 Level 1 (0 points)

    Hi Pondini. I have been having the same problem as Pamela. I did a full reset as per your directions, but Time Machine is still not backing up automatically. Is it possible that the plist file has managed to get itself corrupted yet again?

  • nbar Level 5 Level 5 (6,975 points)

    Pondini!!! The man, the myth, the legend.

     

    http://pondini.org/