There is nowhere mentioned about this bug in the application. I have checked official website and any other websites that mentioned Advisor Care Center. However, if you can't use the built-in Defragmentation feature, then I recommend picking something else. For example, Defraggler does the same job and it's available for downloading and installation. I have used application on my computer as well and it works just fine.
Download it here: https://www.piriform.com/defraggler
Additionally, if you don't want to use Defraggler, then re-install Advisor Care Center and then launch it with Administrator access.