How to force Mac OS X ML not to auto connect to Wi-Fi For my work I need hundreds of open tabs in my Chrome. When I restart, Mac automatically connects to Wi-Fi and all tabs get loaded which consumes much memory. I don't want this.

What I have to do is manually turn off Wi-Fi, then launch Chrome. When all tabs get loaded with "Unable to connect to the Internet", I turn on Wi-Fi. This helps me not waste memory on unused tabs.

So, is there a way to force Mac not to auto connect to Wi-Fi? I still need it "Remember networks this computer has joined" since I use my company's secure network and I don't want to reenter all the credentials all the time.
Go to the network preferences, select "Wi-Fi", and click "Advanced..." (you may have to click the lock in the bottom left first).  Then, in the "Preferred Networks" list, delete any that you don't want. 

The passwords are saved separately, in the keychain.  I have verified that removing an SSID from the list in the network preferences doesn't remove it from the keychain, so you can delete them without worrying. (this is unlike the case with iOS, where forgetting a network also forgets the password)

You may also want to uncheck "Remember networks this computer has joined" to prevent them from being re-added when you join them again.   Again, this is separate from the "Save password in keychain" that saves the password in the keychain when you enter it.