Hi everyone. I have been using Avast Free Home Edition for years but decided I would try the Professional version after reading such good reviews. I uninstalled the Free version using the Avast uninstall cleaner. After I had finished that, I went into the registry and cleaned everything that was left that mentioned Avast. Then, I started trying to install Avast Pro trial and I got an error message stating there was no previous version mentioned in the registry and there wasn’t a folder either. I tried this several times after rebooting but nothing changed. So, I gave in and reinstalled the free version again and then tried installing the Professional version again. It went through the procedure this time but when I open it up it says Avast Home Edition. Plus, when I try to switch to Enhanced User Interface, I get the message “Sorry, this feature is only available in the Avast Professional Edition”. That was suppose to be what I am trying out but it doesn’t sound like it is. Is there a way I can uninstall the Home edition and install the Professional trial version without having to install the home edition first. That way I can be sure it is the Professional edition I’m using. Thank you in advance for any help you offer. 
I suggest an installation from the scratch:
- Download the latest version of avast! Uninstall Utility and save it.
- Download the latest avast! version and save it.
- Uninstall avast from Control Panel (if possible). If, for any reason, you can’t run it, try booting in Safe Mode and doing it from there. Anyway, boot after that.
- Use (run) the avast! Uninstall Utility saved on 1. If, for any reason, you can’t run it, try booting in Safe Mode and doing it from there. Anyway, boot after you’ve run it.
- Install avast! using the setup saved on 2. It will be good to accept the boot time scanning. Boot.
- Add your Pro registry key. You can install avast trial for 60 days, 2nd installation, only 6 days.
- Check and post the results.
How do I get a Pro registry key? I checked the Pro registry key in the about feature and it was different than my Home edition key. This Pro key was S9999999T9902A1106. Is it suppose to be different than that for the trial version? I received all of this mess installing it from scratch. I had used the Avast Uninstall Utility you mentioned and did it in safe mode but nothing has changed. What is going on? Do I need to get a different key to make it change to the Pro. version? If so, how?
The S serie key is a trial one.
The Pro key you must buy at www.avast.com. Of course it’s different from the trial and from the home version.
The trial version is the Pro with time limitation.
I’m wondering now if I’ve found my problem. When I downloaded the trial version for the first time from Cnet, it downloaded so fast I couldn’t believe it did it but it was there. So, I tried it again and it was the same. I just downloaded it from the home web site and it took much longer and the file size,etc. is different. Could this have been my problem? Can I install this version and use it as a trial? If not, I’m back to the same problem.
The small download is the on-line setup. It just connect and then download the necessary files to install.
The big download is the trial version. But, if you have uninstalled avast once, the trial will last only 6 days (and not 60 as the default). This is an anti-piracy feature.
It was the small file that has caused all the trouble. It wouldn’t do anything but give me the error message so it couldn’t connect and download the necessary files.
6 days isn’t enough to know how a program is going to work. It sounds like I had better just forget this program altogether and go to another brand. The home page encourages users to download from Cnet so I was just doing what was advised but now I wish I hadn’t. :-[ I understand they have to protect themselves agains anti-piracy but the cnet trial version should install better than that if we can’t uninstall it without losing our 60 days. Thanks for your time.
You can ask for a new period (60 days) to sales (at) avast (dot) com.
I’m quite sure they will give you that time.
We already complained about that some times. I think the on-line setup is not as good as it sounds like. Maybe they reconsider the release of it.
[quote author=Tech link=topic=47393.msg399906#msg399906 date=1249559513]
You can ask for a new period (60 days) to sales (at) avast (dot) com.
I’m quite sure they will give you that time.
Right now, I don’t know what I will do. I’ve been checking into other programs since my last post and I haven’t decided yet. I don’t like the idea of having to contact sales just for using a trail version for more than 6 days but thank you Tech for all of your suggestions. I will keep them in mind.
Why not?
When a program gives as much trouble as this one has just to try to use the trail version, I can’t help but be cautious about it. If the trial version is this much trouble, I hate to see what trouble the purchased version would cause me and that’s why. I just can’t help but be a little leery and cautious.
I see… but the problem is that you’ve never get the product running correctly in your system and you’ve tried to uninstall/install it more than once… it’s an antipiracy feature, but, like I’ve said 80 million of people use avast and your computer won’t be that different then theirs, will it? 
I didn’t uninstall it more than once because I wanted to. I only did it because it wouldn’t install correctly. I kept getting the error message stating “there is no previous version mentioned in the registry and there isn’t a folder either” and it wouldn’t install. So, I had to uninstall it and turn around and install the free version before it would get past that and then it didn’t install correctly. Any program that is that big of a pain just to try, I don’t want any part of it. I’m sorry but I’m not interested after all of that.
That’s the error you’ve done… manually deleting registry entries brings the trouble.
Again, to trial avast is just install it (without any previous antivirus being running or bad uninstalled).