Author Topic: Uninstalling avast 6 and installing 5.  (Read 10836 times)

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  • Guest
Re: Uninstalling avast 6 and installing 5.
« Reply #15 on: February 28, 2011, 10:51:16 PM »
I had 5 installed and let it upgrade to 6 and encountered some bugs in 6 (reported elsewhere) that I just couldn't deal with.  When I uninstalled 6 through the normal uninstall process, I also had to run the cleanup tool in safemode and also had to do a registry clean of avast - it seemed that several settings had been retained causing 5 not to work exactly as it did before the upgrade.  After the reg clean, 5 installed and ran without issue.


  • Guest
Re: Uninstalling avast 6 and installing 5.
« Reply #16 on: March 01, 2011, 07:59:17 AM »
Actually Jack, I'm going to correct you on the order of your post because some things out of order can make a difference and cause install errors, but I thank you for offering assistance. :)

How to Uninstall and do a clean install of Avast:
1. Save a copy of Avast 6.0.1000 and save it to your HDD for the product you want (Free, Pro, AIS).  If you need earlier versions of Avast Free, you can find them on
2. Download the Avast Uninstall Utility and save it to your HDD.
3. Disconnect from the Internet at this time.
4. Go to Control Panel and uninstall Avast through Add/Remove Programs if possible and reboot.
5. If Step 4 fails, boot into Safe Mode (hit F8 repeatedly) and run the Avast Uninstall Tool.  Uninstall all prior versions and products of Avast at this time.
6. Reboot.
7. Install the newest version of Avast and reboot.
8. Get Internet access and register your copy or add the license key for Free, Pro, or AIS.
9. Update the Avast definitions.

Yes, I would also suggest a clean up with something like CCleaner as well after uninstalling (after Step 6), but not everyone does this; this is my opinion and not Avast.

If you wish to do an upgrade via the Avast GUI from a prior version and experience a problem and want to try an Avast Repair, you can do so.  However if you experience problems, I would suggest an uninstall and clean install to fix the problem as we have seen this seems to resolve the problems with other users on the forum.

How to do an Avast Repair:
- Go to Control Panel > Add/Remove programs > Avast Antivirus.
- Scroll down and choose Repair function in the pop-up window.
- Reboot.