After installing SP3 for Windows XP in May 2008, Internet Explorer 7 began freezing up intermittently when I had multiple tabs open and closed the tab farthest to the right. It seemed to happen mostly when the tab being closed had contained a form that I had just submitted, and especially if I had closed the tab before the result page had fully loaded. The problem may have been more general than that, but those are the circumstances where I noticed it multiple times.
The tab being closed did close, but the remaining tab (the one that should have gained focus) never became functional, the little "e" icon in the top left corner of the IE window turned to a white empty window icon, and after a few minutes during which the system was almost (but not quite) completely unresponsive, the attempts to close IE7 finally resulted in a "This program is not responding" error message and a "Please report this to Microsoft" prompt. They must be getting a million of these reports, so I'm sure they're aware of it.
In Tools > Manage Add-ons > Enable or Disable Add-ons, I disabled the following because they (especially the Link Helper) have caused problems in the past:
Adobe PDF Reader
Adobe PDF Reader Link Helper
In addition, I uninstalled
the StumbleUpon Toolbar, even though it was already disabled. I had installed the IE7 version of the toolbar in early June, and it crashed IE7 within 5 minutes of use! Not impressive. I disabled it and left it that way. When these new crashes started occurring, I uninstalled the Toolbar entirely by logging in as an Administrator and getting rid of it in Add or Remove Programs.
I don't know which action solved the hang-ups, but it does appear to be an add-on related issue. You can test it by going to:
start > All Programs > Accessories > System Tools > Internet Explorer (No Add-ons).
If IE7 stops hanging up, launch IE7 normally, then go to Manage Add-ons and start disabling Add-ons until you find the culprit.
A couple of hours after posting this, IE7 crashed again, except this time it wasn't due to closing a tab (that hasn't happened since the fix, at least not yet), but after task-switching to Microsoft Word and back. Update July 18, 2008
After 3 weeks of no problems, IE7 froze again this morning after closing a tab. This time, it seemed as though an advertisement might still be loading into the page that was supposed to receive focus when I closed the other page's tab.
On the notion that maybe the problem has something to do with the behavior (coding) of the page and that advertisements are sometimes the bleeding edge of new behaviors, I've taken the drastic step of blocking the two ad networks whose ads were displayed on the page that crashed IE7. I did this by entering the (possibly) offending URLs in Trend Micro PC-cillin's Web Site Access Controls feature. When a site is blocked this way, PC-cillin blocks the outgoing request
and thus will not even allow the content to be fetched from the specified website. Details how to do the blocking are near the bottom of the page at How to block ads from web pages in Internet Explorer and Firefox
. I won't say which ad networks I blocked, since this is only a test.
I also mentioned PC-cillin on purpose. If anyone else having this problem is also using Trend Micro Internet Security, I'd like to know. I tend to think that in this case TIS is probably not causing this problem, but I can't rule it out. Update August 18, 2008
No crashes so far since I started using PC-cillin to block the ads from being fetched.
When the freeze-ups occurred, it seemed in retrospect that there was one popular website that I often seemed to have open in one of the tabs at the time of the freeze-ups. That site draws ads from numerous different ad networks. Nowadays, whenever I'm at that site and notice an ad showing, I use Page > View Source to discover where the ad is coming from. If it's from any place other than the main company's site that I'm on, I add that outside domain to my block list.
A possibly confounding factor is the August 12 Windows Update. It's always possible that it fixed something in IE7 that was causing this problem, which would make it difficult to know what the real solution was, assuming that it actually is solved... Update October 7, 2008
So far, the problem has not recurred since I made the changes described above. Update May 8, 2010