Debugging shell-extension that causes windows to freeze

Question

For some time now, I have been living with and working around an annoying problem in Windows XP whereby any time I open a file dialog (Open/Save) in any program, not long afterwards, that program will hang (the GUI will completely freeze and “ghosts”).

I have done extensive tests and can confirm 100% that it is file dialogs that are the problem. directory-selection dialogs do not cause the problem.

The obvious explanation is that some shell-extension is misbehaving, but I am having difficulty determining which one.

I tried using ShellExView and Autoruns to disable shell-extensions, but that did not help, especially since there are 333 items in ShellExView and 154 items in Autoruns, so disabling and rebooting for each one would be a nightmare (particularly because even though the problem is consistent, it is not immediately reproducible; I have to just kind of wait for it hang some—random?—time after).

Does anybody know of a way to find out what shell-extensions would specifically affect file dialogs?

^{(No, there are no network-mapped drives.)}

Answer 1

I know it's not a quick process, but disabling extensions and then re-enabling them is really the best solution. Any of the shell extensions may be interacting in an unexpected way with the file dialog.

You don't have to test them one by one. Using a "binary search" will reduce your number of necessary explorer restarts to 9 in the worst case (assuming that just one extension is causing your problem).

1. Disable half of the extensions (~166).
2. Terminate explorer and then restart it.
3. • If the problem is gone, re-enable half of the disabled extensions (~84).
   • If the problem is still present, disable half of the enabled extensions (~84) and re-enable the previous group of disabled extensions (~166).
4. Repeat from step 2.

To terminate explorer gracefully do one of the following:

• log off
• XP specific: bring up the shutdown dialog, press and hold ctrl-alt-shift and then click the "cancel" button.
• Win7 specific: ctrl-alt-right-click the start menu (not the start button) and select exit

As long as you test half of the remaining group of extensions at a time, you will narrow down the field very quickly. The possibilities drop from 333, to 166, to 84, 42, 24, 12, 6, 3, 2, to 1 and then hopefully that last one is your culprit. Along the way it may become obvious which ones are more likely to cause problems and you can switch from a 50/50 strategy to 60/40 or 80/20 if you're really feeling confident.

edit: I should mention that I found this question because I was attempting to debug a network drive slowness issue caused by a shell extension. I used this exact process to find the cause. Only took about 15 minutes.