After updating to the latest of avast pro 17.6.2310 neither Firefox or explorer will start, it crashes right away, went back to previous version and problem is gone.
I’m on Windows 7 Pro x64, I’m experiencing this on 3 of my systems.
Thanks for the reply but it seems the problem still exists even after manual update of VD I guess I will stay with the previous version for now
OK, no problem.
Vapor, can you please try to disable self-protection (UI → Troubleshooting), rename “snxhk.dll” / “snxhk64.dll” and run your web browser again if it helps? Thanks.
Yes the renaming of the dll have fixed the crash problems, thanks. Does that effect programs functionality in any negative way 
Rename “snxhk.dll” to “snxhk64.dll” and vice versa?
Sorry for asking, I just want to make sure…
I have the free version it is telling me to update to this one says my computor is not fully protected if I dont. How to i get out of this. current program is 1752303 and current virus definitions is 1709102 and wants me to update to program 1762310. I tried calling the avast help number always being put on hold or iget someone i cant understand a word they are saying. Help not computor smart here. all the bad reports on this I dont want it.
If you mean you don’t want to update to the 17.6.2310 version, set the AvastUI > Settings > Update > Program > Settings > Manual Update.
You can also go into the Notifications area of the avast UI main window (the Bell icon at the top right of the UI) and you can set the Program Update notification to Ignore.
Forget the free support telephone number that is a 3rd party support company contracted to give limited program support. By far your best option is to come to the forums, were for the most part it is avast users helping other avast users.
Based on your suggestion I changed the filename snxhk.dll to snxhk64.dll and snxhk64.dll to snxhk.dll then all my browser work now.
Vapor - or anyone else with this problem, we’re not able to simulate it in our lab. Can you please rename “snxhk.dll” / “snxhk64.dll” back to original name, run your web browser and when a crash window is shown, run Task Manager and create dump of those processes? Can you please compress them (7z/rar) and upload on our ftp (ftp.avast.com) ? Thanks.
I have uploaded dumps of chrome to the ftp.
Vapor - or anyone else with this problem, we're not able to simulate it in our lab. Can you please rename "snxhk.dll" / "snxhk64.dll" back to original name, run your web browser and when a crash window is shown, run Task Manager and create dump of those processes? Can you please compress them (7z/rar) and upload on our ftp (ftp.avast.com) ? Thanks.
Strange that you can’t reproduce this behavior since not only 3 of my systems running into the same thing but many users reporting the same issue as well
My nephew who has the free avast called me up last night with the same problem 
The archive is password protected…
The password is virus as per the FAQ
I already had a filenamed snxhk64.dll. I renamed the file snxhk.dll as snxhk.dll(2) and now my browsers work again.
Im having problems with my browsers after installing latest avast free update . Chrome and Firefox start for a second in task manager then stop . I have the same problem with AVG .
Running 64 bit Windows 10 Home version 1607 , os build 14393.1198 .
Uninstalling avast or avg fixed my problem.
Could not rename the two files to check if this fixed because i get an administrator error .
Reread Reply #4, you need to disable Avast self defense first.
jocobralex,
changing to another av is not a fix.
It is running away from the problem.
It helped me.
Both ways are good:
- Renaming just snxhk.dll to snxhk.dll(2) freed browsers
- Changed filenames snxhk.dll to snxhk64.dll and snxhk64.dll to snxhk.dll also helped
Thanks for the clue! But no thanks to Avast for several lost hours of my Sunday! >:(