This means one of your Control Panel applets is corrupt OR, more likely, that you have a Logitech web cam installed!

Logitech's Camera Control applet (camcpl.cpl) has a bug that causes stack corruption (and a sub-sequent crash) on ANY applications that try to enumerate items in the Windows Control Panel. Windows itself is able to survive this, but other applications are not. Because the problem is not apparent on Windows itself, Logitech has turned a deaf ear on all requests to fix this bug on their camcpl.cpl applet.

The only solution so far is to rename the camcpl.cpl file that you can find in the \windows\system32\ folder to camcpl.bak, and rename it back to camcpl.cpl when you need to use it again. You should also complain to Logitech and ask them to fix their buggy Control Panel applet.

Whoa! you figured it out! Rock on.

Are there any "open source" or generic webcam camera controls we could use?

Figured it out? You have no idea the headache this problem has given me already! And I don't even own a Logitech web cam!

All testing had to be done through 3rd parties and dozens of private debug builds - kudos to Neville Collins for having the pacience of a Saint!

Logitech itself has given me the run around, and I don't think they have any intention of fixing this problem - after all, their %$$ buggy control panel applet *seems* to work fine with Windows. In the mean time, Winstep is probably losing customers because of this: imagine you just installed WorkShelf, open the Control Panel shelf and bang! WorkShelf simply disappears... Who are you going to blame?

I'm just about ready to go buy a Logitech web cam to see if there is *some* way to prevent WorkShelf and NextSTART from crashing because of it - which seems pretty difficult given what is actually happening here (stack corruption when you enumerate the items in the Control Panel - you don't even crash immediately, you crash when you return from the sub-routine because the return address has been overwritten by camcpl.cpl).

Whoa! Easy with the big long scary programming terms...

I am just impressed that you were able to at least identify the potential problem. It's a lot more than I can do: "Hey! NS keeps crashing!"

The work around I use is to have NS actually open the control panel window. I don't have a WS control panel tab.

For what it is worth, I am clearly still using WS, inspite of the labtech issue

And by the way, if anybody reading this has this problem, please post here. I would like to have an idea of how many users are being affected by this.

Thanks for responding to my email so quickly, Jorge. I am contacting Logitech and complaining about this straight away. I use my webcam daily and changing the name of the offending file just isn't a convenient or simple solution for me - I'm sure there are others who feel the same. I'll let you know what kind of response I get

Oh, I know what kind of response you will get - basically you will be given the run-around. But, maybe, if enough people complain, someone there might *actually* look into it.

I am also having the issue. I didn't relate it to my addition of the Logitech webcam until you mentioned it. I rarely go to my Control Panel; only when I loose my sound icon from the system tray. Because I am always trying new utlities and drivers, I typically rebuild my laptop yearly and was thinking I was at that point.

If Logitech's applet is not playing nice, I will certainly raise it to their support group. I am reviewing webcam for 50+ people in my orginization and this would knock Logitech off the short list. There is only two of us who run Winstep but we are the two who count the most (CEO and me).

It'll require showing your windows taskbar for a minute, but you can make your sound icon always on. Right-click on a blank area of the windows taskbar, choose properties, click the Customize button towards the bottom on the right, find your sound icon, and set it to Always show. Click Okay, click Okay again, and your icon should never disappear from your systray again (at least until you update your sound software).

I've been banging my head against the wall for a long time now, trying to solve this issue. I've even bought a Logitech web cam JUST so I could have their %$#"!%$ Logitech Camera Control Applet in My Control panel (it won't show unless the hardware is present) so I could pin-point the instruction where the stack becomes corrupted.

For the technically minded, I managed to track it down to the IEnumIDList::Next method. When the shell enumerates the Logitech Control Panel DLL, it calls a function in it that ends up corrupting the stack. On return from the enumeration sub-routine, both NextSTART and WorkShelf crash because the return address has been overwritten by the buggy Logitech applet.

This is not a problem with my code because I managed to reproduce it every single time with other applications that display the contents of the Control Panel. All of them also crash when the Logitech Control Panel applet is present on the system.

I've yet to solve the problem to my satisfaction (you only know you just enumerated the Logitech applet AFTER the fact, when you get the Display Name, and by then it's too late to do anything - you know you are going to crash on return from the subroutine but there is nothing you can do about it).

However, I did find a temporary work-around for those afflicted by this problem:

1 - Create a new folder in your hard drive.
2 - Open Control Panel in Explorer.
3 - Drag the Logitech Camera Control icon into the folder you just created. This will create a shortcut to the Logitech applet that can be used to run it.
4 - Download and install Microsoft's excellent (but unsupported) Tweak UI for XP, if you haven't done so already.
5 - Run TweakUI, click on the 'Control Panel' item and UNSELECT the 'Logitech Camera Control Panel' entry.
6 - Click Ok.

You can now safely open the Control Panel shelf in WorkShelf and Control Panel menus in NextSTART. The Logitech applet will not be visible, but you can still run it by clicking on the shortcut stored in the folder you created in step 1.

Whatever you do, DO NOT drag & drop the Logitech Applet (or the shortcut you created previously) into either NextSTART or WorkShelf. Both applications automatically resolve shortcuts so they point to the target file, therefore doing this would cause them to crash whenever you opened the shelf or menu containing the Logitech Applet reference.

In the mean time I'm going to try to automatically provide an automatic and transparent workaround based on the above information whenever the buggy Logitech applet is detected on a system. Stay tuned.

SOLVED!

This problem will no longer exist in the upcoming Xtreme public beta 3 release.

Using the fabulous RegMon, by SysInternals, I figured out how TweakXP prevents the user-specified applets from appearing in Control Panel. You can do this by storing the cpl filename in the 'HKEY_CURRENT_USER\Control Panel\don't load' registry key with a value of 'no'.

So, when NextSTART and WorkShelf detect they are about to enumerate items in Control Panel, they look for the 'camcpl.cpl' file in the Windows system directory. If it exists, then this file is included in the registry key mentioned above - this way Windows does NOT pass the Logitech Camera Control applet in the enumeration that follows immediately afterwards.

Once enumeration has finished, the entry in the registry key is removed (so the user can still see the applet if they open Control Panel in Explorer) and the Logitech Control Panel applet is manually included as a reference to the actual CPL file.

Since both NextSTART and WorkShelf are able to run direct references to CPL files using 'rundll32.exe shell32.dll,Control_RunDLL camcpl.cpl', we are thus doing the equivalent of getting away with murder.

Not thanks to Logitech, though. I'm still bewildered at the different levels of response from Eset (NOD32 anti-virus) and Logitech - they're worlds apart!

This is great NEWS and I'm so glad that you've manage to sort this very annoying issue out. I did log a call with Logitech, but it fell on deaf ears and I was just too busy to keep chasing them.

It kept us busy testing for quite a while though.

You will have my subscription order tomorrow.



Cheers
Neville

Thanks Neville, specially for all that testing! Shame I ended up having to buy a Logitech web cam to solve the problem, hehe.