QUOTE
We have rolled back SD v6.0.1.445 to SDv6.0.1.441. If you currently have SD v6.0.1.445 installed, you can continue using this version.

The reason why we have rolled back to SD v6.0.1.441 is because we had problems with the internal purchase links within the evaluation version of SD. This should not affect any subscribers of SD.
http://www.pctools.com/spyware-doctor/
http://www.pctools.com/spyware-doctor-antivirus/