iMac disconnects when downloading large files

The internet on my iMac is a wired connection, hooked up through my router. It works perfectly fine and never disconnects while I'm browsing, playing games, or anything like that. When I download small files, things are still fine. Whenever I download something that takes more than a few minutes, my connection will shut itself off like clockwork. It then takes a minute or two to kick back in and resume, but then after another few minutes it will disconnect itself again. It isn't my ISP, since my laptop (Windows 7) downloads fine on this same network. My iPhone and iPad also have no problem downloading large files on this network either. What could be causing this strange issue with my iMac?

iMac, Mac OS X (10.7.3)

Posted on Apr 21, 2012 3:43 AM

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3 replies

Apr 21, 2012 5:19 AM in response to Mr Rizz

Please read this whole message before doing anything.


This procedure is a diagnostic test. It’s unlikely to solve your problem. Don’t be disappointed when you find that nothing has changed after you complete it.


The purpose of this exercise is to determine whether the problem is caused by third-party system modifications that load automatically at startup or login. Disconnect all wired peripherals except those needed for the test, and remove all aftermarket expansion cards. Boot in safe mode and log in to the account with the problem. The instructions provided by Apple are as follows:


  • Be sure your Mac is shut down.
  • Press the power button.
  • Immediately after you hear the startup tone, hold the Shift key. The Shift key should be held as soon as possible after the startup tone, but not before the tone.
  • Release the Shift key when you see the gray Apple icon and the progress indicator (looks like a spinning gear).


Safe mode is much slower to boot and run than normal, and some things won’t work at all, including wireless networking on certain Macs.


The login screen appears even if you usually log in automatically. You must know your login password in order to log in. If you’ve forgotten the password, you will need to reset it before you begin.


Test while in safe mode. Same problem(s)?


After testing, reboot as usual (i.e., not in safe mode) and verify that you still have the problem. Post the results of the test.

Apr 21, 2012 2:14 PM in response to Mr Rizz

Back up all data.


Boot from your recovery partition by holding down the key combination command-R at the startup chime. Release the keys when you see a gray screen with a spinning dial.


When the Recovery desktop appears, reinstall the Mac OS. You don't need to erase the boot volume, and you won't need your backup unless something goes wrong. If your Mac didn’t ship with Lion, you’ll need the Apple ID and password you used to upgrade, so make a note of those before you begin.


If you have the same problem after reinstalling, make a "Genius" appointment at an Apple Store to have the machine tested. Back up all data before you go.

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iMac disconnects when downloading large files

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