Let it clearly be stated that HDD Diagnostic is nothing which it claims to be and is instead a harmful rogue defragmenter. HDD Diagnostic is actually a direct clone of HDD Control as well as Hard Drive Diagnostic.HDD Diagnostic will do everything within it's given power in order to try and convince innocent computer users that their machines are infected. It is going to be best to try and delete HDD Diagnostic immediately upon detection.
The reasoning behind trying to convince innocent computer users that their machines are infected is so that they will get scared and proceed to purchase the full version when in reality this does not exist and is one big malicious scam.
When it comes to HDD Diagnostic you should be fully aware of the factor that it will proceed to install itself onto your machine when you least expect it without your permission. It will also connect to the internet without your permission as well as slow down your internet connection as well as the speed of your computer system.
You may also receive annoying pop ups and all types of computer security notifications which will alert you to various threats which you have on your machine which aren't real. The only real threat which you have on your computer system is the malicious and deceptive HDD Diagnostic itself. In order to remain safe it is essential that you proceed to terminate HDD Diagnostic off your system immediately upon detection. Rather be safe then sorry at all times.