macbook air Start up itself i didn't even touch.

Reset the NVRAM and SMC.

Resetting the NVRAM/PRAM

Note: This will not delete any data.

The NVRAM/PRAM stores information such as speaker volume, screen resolution, startup disk selection, and recent kernel panic information (if any). You should reset the NVRAM/PRAM if you experience issues relating to these functions.

Shut down the computer by going to Apple () > Shut Down…

Select Shut Down or allow the computer to shut down automatically.

Turn on the computer by pressing the Power Button.

On the built-in keyboard, press and hold the Command (⌘), Option (⌥), P, and R keys before the gray screen appears.

Continue to hold down the keys until the computer restarts and you hear the startup chime for the second time.

Release the keys on the built-in keyboard.

Resetting the SMC of an Intel-based portable Mac with a battery you should not remove on your own

Note: This will not delete any data.

The SMC is responsible for controlling various system functions. None of your data will be deleted by resetting the SMC.

Shut down the computer by going to Apple () > Shut Down…

Select Shut Down or allow the computer to shut down automatically.

Plug in the MagSafe power adapter into a power source and then connect it to your Mac if you have not already done so.

On the built-in keyboard, press the (left side) Shift (⇧), Control (⌃), and Option (⌥) keys and the Power Button at the same time.

Release the (left side) Shift (⇧), Control (⌃), and Option (⌥) keys and the Power Button at the same time.

Also, make sure there is not a scheduled startup time. You shouldn't shut off your Mac while it is charging, either. It is easier to just leave it in sleep, which also installs software updates and backs up your Mac while it sleeps.

To check if there is a scheduled time, go to System Preferences > Energy Saver.

Then, select the Schedule... button in the bottom right-hand corner.

Make sure the box is not checked for Start up or wake.

Learn more about the things your Mac does during sleep here:

http://support.apple.com/kb/HT5394?viewlocale=en_US&locale=en_US

I hope I helped.

No problem! If after a while you find those posts didn't solve your problem, just reply, and I'll take you through a few more steps that can also solve your problem if those steps didn't.

You shouldn't shut off your Mac while it is charging, either. It is easier to just leave it in sleep, which also installs software updates and backs up your Mac while it sleeps.

Can you link to an Apple kb article suggesting that you do not shut it down while it is charging - please. I've had Macbook/Macbook Pros for quite a few years and always shut them down when I'm done whether it is charging or not.

I only use the MBP a couple of hours a day, so it gets shut down when not in use. The software updates/back ups do not apply in my case as I only check for updates manually (nothing gets downloaded or installed here unless I see it first) and I do not use Time Machine.

It is just my opinion that you should not shut it down while charging because there is no reason do so.

Ahh, ok, so there is no official recommendation; I'd word it as such then as there may be several reasons to shut it down - whether that be personal preference or the fact that you'll be traveling or not using it for some time.

Ok.

I'm replying to myself because your post only shows in the RSS feed - the forums have been glitchy for 2 days now not showing some posts for an hour or more. Annoying. In any case - great!

I know. I keep replying to your old posts because I get the new ones in my email. A few hours ago it wouldn't even let me log in.

It's the Jive software used to run them and the fact that these are the single most busy forums anywhere (I think).