Have you ever installed Safari 6? Did you install Safari 5.1.7 via the instructions here, or have you merely avoided updating Safari for the past couple of years?
At any rate, Safari has improved their Web Inspector in recent versions – so my original reasons for downgrading no longer apply. I'd recommend just updating to Safari 6.
It was available on mine – presumably by default, as I don't recall ever installing it. Feel free to use whichever version is supported by your system
In your case, it's probably much easier to just use a different browser (Chrome or Firefox)
My simple reply is... there's no good reason :-P
I've always used the openssl command. I wasn't aware that base64 was available as a standalone executable.
Thanks for sharing. I'll probably switch to this technique instead – as it's more terse and removes an extra step from the process.
Sorry to hear. I wrote this post while using 10.7.3, and was downgrading from an older (mid-2012) release of Safari 6. If your system specs are different, then these instructions may cause issues. Hopefully you can reverse the steps above (re-enable the Safari frameworks, and use Pacifist to uninstall Safari 5). If that doesn't work, then I'm not sure what I can suggest
Can you be more specific with the "OS upgrade" message that you're seeing?
Since writing this ProTip, I've upgraded to Safari 6 once again with no problems. I am still using Lion. I never got a message about upgrading to 10.8
If Software Update doesn't work for installing Safari, then try renaming the frameworks to their original names, as described in my previous comment
Can you provide some more detail?
"Didn't work" = Safari tries to start, and then crashes? Or it fails to start at all?
Are you using 10.7 or Mountain Lion? These instructions are Lion-specific, so if you're using ML then there's little information I can provide to you.
And are you sure that you completed all the steps above? OSX might still be seeing some of the Safari 6 frameworks, and assuming that it's installed correctly (therefore not providing it in the Software Update).
If all else fails, just restore the frameworks to their original names (I'm presuming you --backed them up-- instead of deleting them entirely). Unfortunately, Apple hasn't provided a standalone .PKG for Safari 6. The only way (that I'm aware of) to install it is via Software Update (or by reinstalling Mountain Lion).