Sleep mode not working with Lion on my MacBook.

Same here on an imac 27 2010

:-/

Take a look at the console. My bug was an error of little snitch! Now the lion sleeps tonight!

(same bug on mb air, the old little snitch app)

Hope it will help

What we have to do?

Isn't checked!!

i checked the console for entries and there i see a lot of events from little snitch, it tickers trough!

then i checked the little snitch logo above, it was gone. so i tried a reinstall of little snitch (with reboot). After this, the imac / lion went to sleep.

greetings

Bob

same here with my imac 27 2009

i also don't have the little snitch app.

when i turn off internet sharing it goes to sleep after some time, but not like under SL where it went to sleep in about 2 seconds

I turned off Internet Sharing and now it goes to sleep but also it takes so much longer than under SL

Mi macbook doesn't wake after sleep!

Yes I just realized the problem myself. I have a late 2008 MacBook Pro that's hooked up to a second monitor. With Snow leopard, my Macbook would sleep without problems while the second monitor would fade to black. Now with Lion, if I close the lid to sleep, my desktop jumps to the second monitor and stays awake. Odd....

Same thing here and I will say it's a Lion issue. I did a fresh install of Lion booting from USB drive. Erased the HD and completely started a new install. No TM restore, no Archive install. Clean as clean is going to get. Created the first account after install. First thing I did was go into Energy Saver and set Computer Sleep and Display Sleep to 1 min and let it set. The screen turned off but the mac never went to sleep after letting it set there for 15 mins. So consiedering this as a freash install with no user configration there's a problem with it. I have 2 late model C2D Macbook and MacBook Pro both are having different Sleep issues. Macbook won't sleep and MacBookPro sometimes won't come out of sleep. Then I also have a new i5 MacbookPro that seems to be fine and a brand new 5 day old iMac that also seems to be fine. So maybe it's a older hardware related issue. Maybe Core 2 Duals are having the issue. ???

If your MBP has no MagSafe on it, it goes to sleep also with an second monitor...

This fixed it for me: stop the Share Internet feature.

Thanks!

That's assuming internet sharing is turned on. In my case out of box installation with nothing turned on.