OS X Lion is incredibly slow (even after index)

I've installed Lion on my iMac (24-inch, Early 2008, 3.06GHz Intel Core 2 Duo, 4GB RAM) and it has become INCREDIBLY slow. I've heard many people saying that the machine would return to its typical blazing speeds after indexing finished, and it has — I've left it on overnight a couple of times to make sure everything finished, and it's still much slower than it was while running Snow Leopard. Virtually every application hangs — when typing in Finder (for example to rename a folder) the text lags several seconds behind what I'm typing. Mission Control is terrible — the graphics lag behind and it takes several seconds for the animation to finish. Often the animation doesn't appear at all, and it just flickers between frames awkwardly until the mission control display finally appears.


I'm working on backing up all my data and doing a clean install … I'll see what happens, but if it doesn't work I'm going to have to roll back to snow leopard, because this is ridiculous. I've never seen an OS change slow down a machine so much since Vista … hopefully it's fixable. Any thoughts on what might be the cause?


(Oh, and activity monitor scans look normal … nothing's hogging the CPU, and there's slightly less than 2GB of RAM free almost all the time.)

iMac Core 2 24, Mac OS X (10.7)

Posted on Jul 23, 2011 11:59 AM

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288 replies

Sep 18, 2011 10:54 AM in response to Pyro7i9

UPDATE: So repairing permissions worked for about a day and a half before my computer became slower than ever before. I decided to do a fresh install of everything and it is now blazing fast. I'm hoping that this is a permanent fix. If I begin having issues with this installation, I will be moving back to Snow Leopard. It has Rosetta support anyways.

Sep 20, 2011 5:17 AM in response to jswin

So after a LOT of fear, I decided to do the clean install followed by a Migration assistant import of all my applications, files, etc.


It WORKED. It's all zippy again. Just make sure your time capsule has the absolute latest copy of all your data, make the backup DVD, reboot and boot from the DVD, format, install, and then migrate.


Happy days are here again!

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OS X Lion is incredibly slow (even after index)

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