How to get rid of missing plug-in alerts

Sorry, but you can't get rid of those error messages, and there's no such thing as a dummy plug-in. The best you could hope for is to disable JavaScript and Plug-ins in Safari's Preferences>Security section, but that may leave you unable to use the website at all.

Well, I guess you're right regarding the alerts ; they're unavoidable.

But, regarding the dummy plug-in, I actually did it. It's quite simple : you just have to create a new project (in XCode) based on a web plug-in template, change its name according to your taste (I chose "My Dummy Plug-in" ...) and, most importantly, assign the right MIME/Type to it (in my case : "application/x-scort-kbd"), in the "info.plist" file.
Build it and install it in your ~/Library/Internet\ Plug-Ins/ folder and that's it !

You simply have to relaunch Safari and it's working as expected : no more alerts and the embedded content is ignored, which is exactly what I wanted. You even can put it in the global folder (/Library/Internet\ Plug-Ins/).

By the way, if, in the future, other embedded contents need some particular (and unavailable) plug-in, I suppose you only have to add some extra MIME/Type to the dummy plug-in information file.

That might work if you're a developer, know how to code and use Xtools, but the average user doesn't meet those criteria, so it's not a solution for them.

An alternative method of not getting the "Safari can't find the Internet plug-in" alerts is to have all the necessary plug-ins!

These are the downloads and the settings you need in order to view/hear/play pretty much everything that the net can throw at you: The setup described below has proved repeatedly successful on both PPC and Intel macs, but nothing in life carries a guarantee!

It is known to work in the great majority of cases with Safari 3 and 4, QT 7.4.x, 7.5.x and 7.6 and OS 10.4.11 and 10.5.7.

Download and install ( or re-install even if you already had them) the latest versions, suitable for your flavor of Mac, of:

RealPlayer 11.1 for Mac from:

http://www.versiontracker.com/dyn/moreinfo/macosx/15540

Flip4Mac WMV Player from http://www.telestream.net/flip4mac-wmv/overview.htm (Windows Media Player for the Mac is no longer supported, even by Microsoft)

Perian from http://perian.org/

You should read this support page http://perian.org/#support in case you need to delete older codecs.

The latest version of Adobe FlashPlayer can be obtained from here:

http://www.adobe.com/shockwave/download/download.cgi?P1ProdVersion=ShockwaveFlash

(You can check here: http://www.adobe.com/products/flash/about/ to see which version you should install for your Mac and OS.

It is suggested that you first uninstall any previous version of Flash Player, using the uninstaller from here (make sure you use the correct one!):

http://kb.adobe.com/selfservice/viewContent.do?externalId=tn_14157

and also that you follow the instructions closely, such as closing ALL applications first before installing. You must also carry out a permission repair after installing anything from Adobe.

You should also ensure that you have downloaded and installed the correct version for your Mac of Security Update 2009-001 (and for Tiger only, 2009-002). (N.B. Security Updates require both a restart and a permission repair.)

In Macintosh HD/Library/Quicktime/ delete any files relating to DivX (Perian already has them). However it should be noted that Perian is not an internet plugin and will not play DivX files imbedded on a website. For that you will need the DivX Player browser plugin available from http://www.divx.com/divx/mac/

Now go to Safari Preferences/Security, and tick the boxes under Web Content (all 4 of them) to enable Java.

Lastly open Audio Midi Setup (which you will find in the Utilities Folder of your Applications Folder) and click on Audio Devices. Make sure that both Audio Input and Audio Output, under Format, are set to 44100 Hz, and that you have selected 'Built in Audio'.

Important: Now repair permissions and restart.

You should also consider having the free VLC Player from http://www.videolan.org/ in your armory, as this plays almost anything that DVD Player might not.

There is an additional 'fix' you could try if you are having problems with Flash and Quicktime, depending on which type of Mac you have:

On Intel Macs, make sure that you are not running Safari in Rosetta. You can check this, and change it, in the Get Info window.

On PPC Macs, go to the Hard Disk/Library/Internet Plug-Ins folder, and drag the file 'QuickTime Plugin. webplugin' to the desktop. Quit and restart Safari. If things have improved you can trash that file. If they haven't put it back, as the lack of this plug-in can cause QT content in some widgets to cease functioning.

And there is an additional kid on the block: SilverLight. Microsoft has created their own version of what a replacement for Flash could be. You can read more about it here:

http://silverlight.net/

So, if you go to any sites that have been designed for this new Silverlight stuff, you can download the plug-in from here (but make certain that you are downloading SilverLight v.1.0 for OS X (10.4.8 upwards) if you are using a PPC Mac. Versions 2 and 3 only work with Intel Macs:

http://silverlight.net/GetStarted/

Recommendation: Close all applications before installing any of the above, repair permissions, reboot, and repair permissions again.

Klaus is right, you need to have the proper plugins install. That's the only way to get rid of the plug-in alert.

I chose not to have Silverlight and real play installes. That's on me...if I come to a site that needs those two plugins, I simply don't stay on that page.

I don't make a federal case* out of it when I don't have the proper plugin or look for a workaround when I know what the problem is...

Hacking Safari with plugins isn't the solution. Doing so only invites other problems.

*A major issue that has evolved from a minor problem.