AV locks up computer

Every time I start a scan it will lock up my computer. I have to manually power off my machine. This used to only happen if I tried to select another program before the scan actually began, but after the dialog has started. Now the freezing happens all the time. Uninstalling and reinstalling does not help. I had no other security software and am running XP SP3. I finally said enough is enough and uninstalled CIS and reinstalled it without the AV and am now running Avira.

Sme was happening to me. Though CIS works fine now. But it seems the bug still exists :-\

Yup, same here. I reported this issue in beta of 3.9. It seemed to be fixed, but CIS still can hang sometimes. It hangs only on certain files/folders. In my case the issue only affected NTFS disk partitions.

If you can pinpoint the file/folder which is causing the issue and it is small enough to upload it to FTP then you should contact someone from Comodo’s Staff to help solve this issue.

It just happened to me just now…

The entire computer was still running, but the Clock and everything else was going SUPER SLOOOOW…

In the end I had to press the Restart Button after 20 minutes of NOTHING… :(…

I “canceled scan” and it NEVER turned off, just sat there with the animation and you can “turn/cancel off scan” forever and nothing would happen…

I pressed CTRL+ALT+DEL for the Taskmanager and even on the bar but nothing happened…
Pressed the START button, still nothing happened…

When starting your scan, is your computer connected to the internet?

I ask because I have noted a similar problem when initiating a scan w/o internet connection. AV locks up the computer when trying to reload the A/V database.

I am seeing lock ups as well. I haven’t been able to run a complete virus scan with CIS yet. It hangs every time. I’ve deleted the file it hangs on, then it runs a little further and hangs on another file.

My experience: run a scan (manually or automatic)(heuristics low or off)
After 5 to 10 minutes it appears hung. The file name isn’t changing, but the timer is still counting. It will sit like this for more than an hour. Upon clicking to close the window, and being asked if I want to cancel the scan, I say “yes”. Now the window is still there, but all the buttons are grayed out. Also the computer is unresponsive (ctrl-alt-del doesn’t even respond). But the timer on the antivirus window is still counting. After waiting a few minutes, I hard reboot to get my computer functional again.

My Info:
* CPU 32 bit
* Operating System - XP Home SP3
* Defense+: clean
* Firewall: safe
* Administrator account
* CIS version 3.9.95478.509

There was a problem with CIS if DEP was turned on. Not sure if this is still an issue. I still DEP turned off for CIS.

This issue still has not been resolved. What is needed by comodo people in order to help with this issue?

U might have conflicting software, something about "shell integration or shell extension" don't know the whole mombo-jombo to explain to u as I'm not a computer geek, I had similar simptomes with a security software once (was hungin' and crashin') and I was advised by a friend who in fact is a computer geek to do the following:

download latest version of ShellExView (freeware software) and install it and it will show u all the software on your system that are “shell integrated or shell extensions”

u will notice many columns and one of them is named “Company” and it tells u which company is the software from

all the software that are not from microsoft except Comodo software must be selected by pointing right-click on it and select Disable or multiple using Ctrl

close the ShellExView software and reboot (can’t remember if u must reboot but do it anyway)

try using Comodo scan now and see if it still hungs or crashes !!!

             This is how I got my problem solved, I use win xp sp3.

Sorry if this post doesn’t make sense or for the ■■■■■■ edit, I’M DEAD TIRED, must go to bed but I will come back soon !!!

Maybe this can help, I never got an answer from the guys where I posted this !!!

i have same problem, what is DEP?

DEP = Date Execution Protection
System Properties->Advanced tab->Performance settings->Data Execution Protection tab

I have “Turn on DEP for all programs and services except those I select:” selected.

At one time CAV(CIS) would hang doing a complete scan until I excluded it from DEP.
I no longer have CIS in the list at all. I just ran a scan “My Computer” without any hang.

I should note this is on XP Pro SP3+

Hello all. Jim_ said in his post.Go into system properties in control panel and click on advanced and then click to exclude Cis, from Dep.This seems to be a workaround to stop av freezing on certain files. I say this because i experienced a freeze today for the first time in months and assume the next bug fix this week with Cavs will sort this out again!.

However i did a scan immediately afterwards and it worked. Nice one Jim_. I stress this was Xp Sp3 and have not experienced anything like freezing for months on Vista, as the problem " seems" to be fixed on Vista.


I removed the exception for CIS from DEP some time ago. Don’t know why I don’t need it anymore. I would consistently get hangs with CAV (not CIS) when scanning the the hard disk with CAV prior to excluding it from DEP. I don’t know if CIS corrected the problem or if the file(s) that caused the problem during the scan have changed. The contents of my hard drive is certainly different now then when I was having the problem with CAV.

You can get it here:https://forums.comodo.com/feedbackcommentsannouncementsnews_cis/comodo_internet_security_311108364552_released-t44417.0.html .