Q: MacBook Air Mid 2012 Yosemite overheating

Thanks to above for suggesting Activity Monitor

My fan was screaming and I thought it was my Win 7 VM running on fusion but then I opened my Act Mon and my iMessage was hung and peaked the CPU at 99%. I forced quit and everything is good now.

Yosemite definitely needs some fixes.

Thanks

CCF

Same issue--late 2010 Air. FRUSTRATING to no end. All my apps running slow.

Word takes forever.

Yosemite on my macbook pro 17 inch mid 2009 has overheated and fried my machine. HDD is toast and the sata cable wont even read another hdd. i am booting externally. which *****

smcFanControl - amazing how the temp dropped and stays cool.  My 2011 MacBook Pro 21" laptop (Yosemite v10.10.3) was overheating and would either shut down, or the monitor would would split the image and act goofy.  The cursor became a vertical dotted line and there was also a vertical distortion bar about 2" in from left margin.  I had to force the shut down, but then my laptop wouldn't boot again.  I took it to a local IT shop, and they made temp fixes (I think to the motherboard) but the same would happen with the heating issue, etc.  The Apple screen would come up with the progress bar, then to solid gray screen and not boot.  About 30 secs or so later it would reboot itself (repeatedly until I forced the shut down).  I did an Option start, and downloaded Yosemite from the internet.  Then I found where someone else mentioned the fan software so I installed it, too.  I am back up and operating with a cool machine.

same here. I'll spare everyone the rant, but in a nutshell: at first I thought it was a hardware error. took it to tech support, spent time and money, and came out empty. they were very helpful, but underprepared (they used cloud tools straight from Apple that detected nothing).

then I thought it was due to there not being an upgrade path from Mavericks to Yosemite. so I wiped the whole thing and installed from zero. the problem came back a few months later.

now I'm about to downgrade to Mavericks.

the funniest thing is that I installed Windows 8.1 via Bootcamp, played lots of games in Steam, and never had any problems. I remember those "I'm a Mac, I'm a PC" ads making fun of Vista because its user base was downgrading to Windows XP... oh well. (ok sorry I had to mention this)

so anyway, I found a tragicomic solution: either downgrade to Mavericks (fingers crossed) or install Windows 8.1 via Bootcamp and never boot into Mac OS again. of course I'm getting a PC after this, and I'm taking legal action as well. see you in court, Apple.

Thank you for this suggestion. I just turned my off and we'll see what happens.

Please download and run EtreCheck, created by one of own helpers here in ASC. It is a diagnostic tool that's very useful to us in finding problems. Also it will give us further specs on your Mac. After it runs post the log file here. It will contain no personal information.

While EtreCheck will check software for issues, often this can be due to dust buildup in the fan and often cleaning it is the solution.