iMac connection timeout? Help please..

Hi dotty4303 - ther could be anumber of reasons for this so let's try and narrow down the scenario.

Where is your iMac and your router located?

What router do you have?

What password is failing? Is it the password to log into your router or the one for your Internet account?

Who is your Internet provider?

Are you able to connect your iMac to your router via Ethernat cable?

Are other devices connected to your router? If so what devices are there?

Cheers

Michael

Did this start just after the upgrade? If so, and you haven't tried it already, you could re-apply the update using the Combo. Using the combo ometimes fixes odd issues after a point update:

http://support.apple.com/kb/DL1659

Not sure if any of the following will help, and you may have already tried several of the suggestions, but Wifi problems seem to crop up a lot on here and unfortunately there doesn't seem to be a 'one fix' solution.

However, sometimes any one of the following may help although, unfortunately, not always. In no particular order:

• Check wifi security - if it's WEP change it to WPA or WPA2 (preferably, as it's more secure)
• Change the wifi channel on the router
• Create a new Network Location: http://support.apple.com/kb/HT5289
• Reboot the router

Also take a look at this link and the links within the article for other ideas. They mainly reference Lion, but still seem to be relevant to Mountain Lion:

http://osxdaily.com/2011/11/06/lion-wi-fi-problems-solution-mac/?utm_source=feed burner&utm_medium=feed&utm_campaign=Feed%3A+osxdaily+%28OS+X+Daily%29&utm_conte n t=FaceBook

...and this link:

http://osxdaily.com/2012/11/30/resolving-stubborn-wi-fi-connection-problems-in-m ac-os-x/

Also, just to rule out the possibility of one of the following being the cause, do you have any anti-virus software installed, or programs that claim to speed up your Mac or otherwise improve security? There are some apps that are known to cause connectivity problems for some users. Those that spring to mind as possible contenders are: Avast, Kaspersky, Norton, MacKeeper and Peer Guardian. Occasionally Little Snitch has caused problems for some if it isn't the latest version running in MLion.

It seems your router is ok since other devices can connect to it. I assume, the password that's failing when using your iMac is the WiFi password/key rather than the actual password for your Internet provider. Make sure your are using the same Security as defined by your router (e.g. WEP, WPA, WPA2, ...). As Paul_31 mentioned, WPA2 would be best, but for now just make sure you're using the same as your router.

Can you log onto the router and confirm the type of security?

What security is your iMac's WiFi using?

Cheers

Michael

Is the Mac still under warranty/AppleCare? If it is, I think a phone call to them is required - especially as it sounds like it's never worked properly.

Is connecting with an ethernet cable a viable option, at least temporarily? Does that work?

Is there not an ethernet cable in the box that the router came in - ISP's normally supply one (that's assuming you've still got the box 🙂).