A reader wrote in to Helproom to ask: "I’ve been using Avast Free Antivirus for some time, but recently discovered that it had installed Dropbox without my permission. I have since uninstalled it, but how can I prevent this sort of thing from happening again?"
Here's how we solved their problem. Also see Best free and paid antivirus for Windows.
Stop Avast installing Dropbox and other piggyback software installations
Sneaking extra software applications in through program installers is nothing new. It happens most often with free software where the author can get some revenue from partner developers for bundling their applications into the freeware installer.
Technically, you will have always given your permission for extra software to be installed, although that condition is usually buried in the small print.
A common example of this sort of bundling is one or more toolbars appearing unexpectedly on your web browser. These can take up more and more space on the screen and turn into a major annoyance even if they aren’t doing anything malicious.
Many software installers give you the option of an Express or Custom option. Most of us want an easy life, so it’s tempting to pick Express. However, this is the way the installer gets to install whatever optional extras it likes.
It’s a good idea to get into the habit of always clicking Custom. Don’t worry, it doesn’t mean the installation will be difficult. You will usually end up simply clicking through a few default options without having to enter anything complicated, but you’ll also be given the option to turn off any options you don’t want installed.
In the case of Avast, it’s the custom install options where you get the chance to say no thanks to a Dropbox installation. Dropbox is an excellent program, but we do think it should be up to you whether or not you install it. The latest version of the free Avast installer does not appear to include a Dropbox installation. It’s a similar situation with the Java updater. If you don’t opt out, it also installs a free browser toolbar.