I have Googled and Googled "tpdfactivedoc control" and found nothing. Avast found it on my PC and Avast, Malwarbytes and Superantivirus scans did not find it. I found similar things without the f in it.
I Googled it too, and found plenty...
Here is a link that might be useful: Look Here!
That is what I found also, but it did not tell me what it was or if it needed to be removed. This turned out to be a very serious problem. I think it was one of those fake warnings and not by avast at all. Avast said it could remove it, I didn't feel it was the right thing to do, but I did it anyway. Another thing that I thought was bad was that when I clicked remove, it would only remove it if I set my home page to yahoo or bing, i think. I went ahead because I new I could reset my home page. After removing it.... FF would not open it said something xpcom needed. Malwarebytes would not run at all. I did a system restore and could not be completed. Finally I couldn't even use IE. I did a reformat and all is well this morning.
Emma, I have had the same sort of thing happen with Avast and my home page and search engine being changed. I think I do not trust this. It seems to be with the "Browser Cleanup" action of Avast. I have used Avast for years but never had this Browser Cleanup function before. I think I do not trust it, and I'm wondering if I can disable that function. I have IE, FF, and Chrome, and it changed all three browsers. I'm having trouble getting my home page set correctly for Chrome, since it wants to use the same page I have for IE.
Okay, I removed the check allowing Avast to check for browser toolbars, etc. that "can be harmful". I also removed the shortcut for Browser Cleanup.
When I installed Avast I removed almost every check mark except the ones regarding protection. When I got that pop up, I did a full scan and it did not find it even though it was Avast that warned me.
I thought the clean up browser was an option. I got rid of Avast and went back to AVG. I quit AVG a couple of years ago because it locked me out of my games. I should have just emailed them and told it was a false positive.
I've been happy with Avast so far, but there is a lot of HATE for the Browser Cleanup tool in several places and you are STRONGLY URGED not to use it. Check the link below and also these:
After reading this thread, I ran Browser Cleanup only to see what it wanted to do. As I suspected, it found just what I wanted it to find: ALMOST NOTHING! It found one unrecognized object in IE which must have been put there a long time ago by Photobucket since I almost never use IE for that site. In Firefox, it decided it does not like my plugin for the HP printer (which has never caused me any problem).
Keeping your browser free from unnecessary plug-ins and toolbars is always the best choice IMHO and this is just another example which proves the point. I'd also advise Avast users to join the Avast forum and ask questions there before automatically trusting their recommendations.
Here is a link that might be useful: Avast Forum
Thanks for the link to Avast Forum. I went to Control Panel and uninstalled the Browser Cleanup part of Avast.