Shell Extension causes crash on Windows 7 x64

[CmdrX3]

I have had a really annoying problem on my PC, which I've narrowed down to being caused by the Explorer Scan shell extension. When Windows first starts up, and I right click on a file, explorer freezes and I have to restart explorer. It only happens when I first switch on, then all is fine and restarting explorer, until the next time the PC starts. I disabled my shell extensions one at a time until only the Avast Scan extension was left. As I can't disable it, I uninstalled Avast and the problem disappeared, I then enabled the shell extension again one by one without any problem. I then reinstalled avast and the problem returned. Uninstalled again and it went away again, so it's definitely down to the Avast shell extension.

I don't know if this is a known problem (or even if anyone is having it) but it may be something that needs fixed whether in this version or V5.

I was going to install the V5 beta and see if it causes the same problem but on reading the limitations and bugs it doesn't work anyway, so there is little point.

[DavidR]

Certainly not a known problem, at least one I know about and I have been on the forums for over five years.

The problem is conflicts can happen with low level drivers/hooks/shell extensions, remove one conflicting extension and no conflict, but not a definitive confirmation as to the real culprit. I know you say you worked your way through then until only avast was left.

I had a similar problem when right clicking files and I hunted the internet and my system for months until I bumped into the most unlikely shell extension, that of SnagIt image capture. I never even considered that but the latest version certainly has a problem. I only found it because of another post relating the same problem and having SnagIt installed.

I used ShellExplorerView (http://www.nirsoft.net/) to view all shell extensions, I don't know which tool you used.

If this is a live system and not a test system the recommendation is not to install as version 5 beta isn't feature complete.

Have (or did) you another AV installed in this system, if so what was it and how did you get rid of it ?
Remnants are one area that can also cause conflict.

[CmdrX3]

Thanks for the quick reply. I use shellexview x64 to see which context menus are running, and the only extensions used that are not OS related and appear on every right click on a file are winrar, eraser and avast. There are others like the nvidia when I right click on desktop or imgburn when I right click on an ISO, but only the three above when I right click on a text file when the freeze happens (but it's not limited to text files).

I understand your point about conflicts, and I don't know exactly which way windows reads the menus, but I would have assumed it would only use the hooks/drivers/extensions for the shell extensions that are used on any particular right click.

I hadn't planned on using Avast 5 beta as an AV, it was simply to test if the same issue occured with it as with 4.8, but as the shell extension in it isnt operational anyway, I saw little point.

I have never used any other AV on this system, or at least under this installation. Avast has been my mainstay for quite a while and although I have dabbled with others have always came back to use AV shortly after but as I say only Avast has ever been installed on this installation of windows.

[DavidR]

It's certainly a mystery and probably more so in x64 OS (which I don't use) as I would have though there would be less in the way of applications with shell extensions that presumably have to be 64bit.

There are certainly a lot of avast users on x64 OSes (though that number would still be a small minority) but so far I haven't seen anything like this in the forums.

Are there any crash dumps created (memory.dmp) when this happens ?

- You might want to try - Program Settings, Troubleshooting, 'Delay loading of avast! services after other system services.' and see if that makes a difference.

[igor]

I'm quite sure it must be caused by another shell extension.

[CmdrX3]

Ok - I took on board your thoughts about another conflict somewhere, so looked at everything that has been installed. I remembered that when I downloaded the drivers for my Logitech revolution, they only had drivers for XP, OSX & Vista. So I used the Vista x64 drivers, which as with many Vista drivers work fine on W7. I also remembered seeing Logitech in the shellexview, although not for a shell extension (I think for the system tray). There is also no context menu anywhere for logitech or the mouse, but hey what the heck. I uninstalled the Logitech setpoint software and boom, problem disappeared on restart, so I'm inclined to go with your theory on a low level driver or hook causing a conflict with avast which obviously was no longer present when I uninstalled avast and returned when reinstalled, Weird thing is though I reinstalled setpoint again and the problem hasn't returned so there is also the possibility of a corrupt file in the setpoint package that was fixed on the reinstall causing some kind of conflict. A corrupted file may also be the reason that it was not a problem you had come across before, as I'm reasonably sure I'm not the only person using Avast, Setpoint and W7 together.

So credit where it's due, you drew my attention away from looking solely at the shell extensions and quite frankly without your input, I wouldn't even have thought about uninstalling the setpoint software, so muchos thankos. Another little niggling frustration I no longer have to deal with. I love the internets, it's like a huge self updating repair manual  .

[DavidR]

You're welcome.

Well as I said when I found what caused my conflict, it was the ,most unlikely of things (although it was a shell extension).

However, it looks like you may have got to the bottom of it and things appear to be working. Just keep it monitored if it happens again then you know what to do, that is the problem with conflicts, they don't seem to have a fixed schedule that they work to.

[CmdrX3]

Ok - one final update, the problem returned shortly after I made a truimphant shout on here about how I'd fixed it (as is so often the case). So I decided to once again start uninstalling software so carried on until I got to the eraser program (which does have a context menu). Eraser was one of my prime suspects, but I'd only disabled the shell extension option so I assumed it wasn't as fault. So after the problem disappeared even after several resets, I guessed I had it sussed. I really like the program so went to see if their was a newer version from the one I usually install from my HD.

There posted in all it's glory on the eraser home page was:

Eraser 5.8.8-beta 1 released!

A relative rapid release for Eraser 5.8.8-beta1 has been made in light of reports that the Shell extension does not work (hanging the computer). This update is meant to address the issue. Please try the beta if you are experiencing the problem. Otherwise, all the other code is the same as 5.8.7.

So at least I know now that my detective work paid off and the culprit HAS now been found (famous last words). 

[DavidR]

Yes, tracking down these issues really isn't easy, as I said it was months before I eventually found my culprit. My problem was intermittent so didn't often galvanise me to doing some more investigation, until almost by accident I bumped into the answer.

It is nice however, to have confirmation like this.

Fingers crossed

[Lisandro]

I had problems with Eraser 5.8.7.
I had to downgrade to 5.8.6.
Other problems were studied here: http://forum.avast.com/index.php?topic=34729.msg407821#msg407821

[CmdrX3]

Well as this no longer has to do with Avast, I will finally say the problem has been solved and the final culprit in neither Avast or Eraser. The culprit is none other than da daaa.............. Microsoft.

Eraser uses Microsoft Visual C++ Runtimes and installs the core files for it to operate, which it does all fine and dandy. Then Microsoft come along with their Visual C++ updates and breaks whatever it is they have broken and causes Eraser to have the right click freezing problem.

I still find it puzzling though where Avast comes in and why uninstalling Avast cured the problem as well - does Avast use the Misrosoft Visual C++ in some way? If so I guess there would be some reason in there somewhere.

[DavidR]

When you right click on a file, I guess avast may try to hook it in preparation for scanning (don't know that for certain), so if something is also hooking the file and that part breaks (as you say) I don't know if that would then cause the lockup/freeze/crash, etc.