Since my last OSX upgrade to 10.7.4, my AirPort Utility window keeps opening up, mostly on startup, but seemingly at odd times as well. It never did this before. Is there a reason it's doing this, and can I turn it off or keep it closed? It doesn't appear to serve any function or require action. I'm a little confused by it.

Check in your login items in Accounts preferences first but I doubt that's it as it does it at other times rather just startup.

Launch Airport Utility and go to Airport Utility/Preferences in the menu bar. Maybe you have the Airport Utility set to notify when there is an update for your Airport base station, or to monitor for problems. You can update the firmware by clicking the update button.

If it's set to open when it sees problems click the amber button next to Status - Warning in the Airport Utility main window to see what alert it's trying to tell you about.

Which version of Airport Utility?
This happened to me to for a while, then stopped without me doing anything.
I share my connection with a couple gamers, so I just figured it was when the Wii or PS3 was connecting.
Just wanted to let you know you aren't alone.

In the prefs I'm seeing options to check for updates and it's set to weekly, as well as checking at startup. But no options to turn notify on or off.

So it's apparently set to "Monitor AirPort base stations", and open if there's a problem that's making the base station blink amber. Help files says it will "provide instruction to help solve the problem", but I haven't seen that yet!

Thanks for your responses.

Monitor for problems should be a choice in Preferences, I thought it was in the same Preferences window as the Check for Updates settings.

If you have an amber light on the base station you can launch Airport Utility and click (double click?) the yellow light in the main window, it will take you to a setting to check what the problem is and an option to ignore the problem if you know it really isn't a problem and just a setting somewhere that varies from the norm.

I don't *think* I caused this entirely new prob, apparently our isp had some weather related issues over the last few days, and the long and the short is I've completely lost contact with my AirPort base station.
I tried messing with the network settings. At some point, the AirPort utility main window appearance changed, with the solid line from Internet to my base station (Beeville) changing from solid to dotted, both Internet and Beeville had amber dots, but everything was working fine.
I investigated and found that I had switched networks from our current working one to another I'd configured way back when but never used.
So I bravely thought I should switch back to the "correct" network, but things went south at that point. I got only one option for "Beeville" which was clicking a "Forget" button. I thought I would just configure everything from scratch.
But clicking "forget" turned out to be a mistake, and now I cannot seem to get my computer to even see the base station. Period.

Any help or advice would be greatly appreciated.

Have you used the reset button?

Ultimately I ended up at Apple's help pages, and tried in ascending order a "Soft reset", a "hard reset" and a "factory default reset". The last one worked just fine, created a new network with (apparently) all the settings of the previous one that I couldn't reload.
So, happy ending! thanks for comments and advice!