I've used Smart Defrag since version 1 and been extremely pleased with it.  And IObit seemed like a solid outfit, on a par in my mind with Piriform.  The app has been trouble-free and efficient, doing exactly as advertised.  One of the better free apps out there in my experience.  The installer would offer to install the IObit Toolbar, but it was easy to decline - no muss, no fuss.

Things have change drastically with Smart Defrag 3.  After multiple installs, uninstalls, reg cleaning, and re-installs on 2 Win7 64bit machines, no love.  It will appear to install successfully, but the instant you click on the SysTray icon or the Settings icon in the app itself, it crashes out.  Same behavior on both machines, after multiple attempts.

So I figured no big deal since Smart Defrag 2 wasn't broken, I'd just go back to that version & wait until the bugs in 3 got sorted out.  I had the old installer for version 2.9, so I uninstalled version 3 and thoroughly cleaned the machine of all IObit remnants, rebooted and ran the 2.9 installer.

To my surprise and chagrin, the installation got hijacked, presumably because it has a 'phone home' function in the install routine, by IObit itself with a re-installation of version 3 on the fly!  Not only that, but it installed, un-bidden (in fact specifically declined in the case of the Toolbar), the IObit Toolbar, Advanced System Care 7 and IObit Uninstaller. 

This hijacking of a prior version install is the first of its kind I've ever encountered and is lame in the extreme.  Lame enough that all those apps are gone now & I will henceforth avoid all things IObit.  Blocking the install of a prior stable, functioning version in this way is simply not acceptable, even if it is a free app.  So back to Auslogics' Disk Defrag.