iMac 21" i5 4 core, mid 2011
Last night was the last straw, during the last few days id tried every thing these posts suggested. Yesterday i did
a fresh instil of 10.7.0 from my iMac HDD, then it had to updated to 10.7.3 that was the combined update..Build 11D50b
Within an hour id let it sleep and every time after ... id loose the wifi..
So last night, i restarted and went into the recovery partition and formatted my HDD, then left over night
downloading a fresh copy of Lion 10.7.3 from Apple It was ready for me this morning to transfer my files from my time machine.
Build 11D50
I ran the disk repair utility after it got going cool no problems. I have done 5 sleep tests this morning all passed, i
left it sleeping for the main bulk of today and i can happily say the wifi connects straight away so fingers crossed
the new copy is the way to go for Mid 2011 iMac's and maybe the later 2011 ones too?