I fixed it, and you'll never believe how simple it was. I launched IE, and (for the first time, mind you) I got a dialog box saying "Google Toolbar is not compatible with IE8 and must be disabled, or check the site for an updated version" (or words to that effect).
There was a button which said "check for updates." I clicked it. It took me to the IE8 Beta 2 Release Notes. Under "Compatibility with third-party applications," it says:
Google Toolbar
Internet Explorer 8 Beta 2 displays a compatibility warning when certain versions of the Google Toolbar add-in are installed. This issue occurs because Internet Explorer 8 Beta 2 and specific versions of this add-in are incompatible, and the installation is unstable. When you disable this add-in, the functionality that this product provides is removed.
For more information and for updates, visit the following Google Toolbar Web site:
http://toolbar.google.com/tbredir?r=ie8_upgrade
I clicked the link and it took me to the Google Toolbar 5 Beta page. I installed it and...VOILA!...I have the Google Toolbar AND the message bar is gone.
What DID happen:
1) Google Toolbar (less than 5 Beta) is not compatible with IE8 Beta 2.
2) If you have Google Toolbar and install IE8 Beta 2 you will get a message bar stating that "
add-ons have been disabled." BUT it will not tell you WHICH ones have been disabled -- One? All? A dozen? AND the Manage add-ons center will NOT show the Google Toolbar
disabled. It will show that it is
ENABLED.
3) Only after having started IE several times did I get the dialog stating that Google Toolbar was the culprit.
4) I installed Google Toolbar 5 Beta and it IS compatible and the message bar is now gone.
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What SHOULD happen:
1) The message bar, which triggers the Manage add-ons box, should state which add-ons have been disabled due to incompatibility. Instead, it states that ALL ARE ENABLED.
AND/OR
2) Launching IE should immediately trigger the incompatibility warning the first time, not after several launches of IE.
If either of the above had taken place I would have immediately gone to upgrade the Google Toolbar.