The same thing has been happening for me for a few days now. I'll get a notification to optimize my system but whenever I open Support Assist it freezes. 

SupportAssist stopped working on my Alienware 17 R3 after the latest update. I suspect it was caused by the SupportAssist Update Plugin. I uninstalled SupportAssist, then manually reinstalled using the SupportAssist Installer from the link below. It works fine now.

 http://www.dell.com/support/contents/no/no/19/article/product-support/self-support-knowledgebase/software-and-downloads/supportassist

I guess ThomasAAT is right. I had the same problem, and in my case I didn't realize it had made the update (as usual in Windows 10 which is quite annoying). I have WIndows 10 Pro and I got a blue screen requiring the reload of Explorer. I only understood it had to do with Support Assist Update when I noted it deleted the icon in the taskbar. In fact the latest version dates from June 8th, when all this happened. I tried Repair and Reset without success. I started considering uninstall and install it again, so that's what I will try.

Thanks

I'm seeing the same problem on my Precision T3600 with Win10 x64.  I'm up to date on Windows patches as well, and haven't tried to run the diagnostics in a few weeks, so it seems to fit with the situations I'm seeing here as well.

SA tries to start and I see the initial window with a grey background and the "squares" (hourglass) within.  Once when it locked up after I killed it for being non-responsive ("SupportAssistUI is not responding") I tried launching it again and saw the "cards" within the startup window but it was still locked up, but I haven't been able to repeat it.

I tried logging out & in again, then rebooting, then updating my nVidia drivers and rebooting.  Same issue.

Me2

Just an update: I went through the apps on control panel (Windows 10 Pro) and uninstall both Support Assist (since I had run the repair and reset it added an additional icon for the app - original and repair). I followed the link provided by ThomasAAT and install Support Assist again and it is working fine.

Also to point out that the sort of behavior in my XPS was exactly as described by Glen...

i am facing the same problema with my 7460 with Windows 10 Pro

I can't even uninstall it as there is a package problem the Uninstall wizard tells me.

Same problem on my 5568 laptop. Started after an upgrade from 2.2.0.253 to 2.2.1.23. Dell Update also seems to be affected :-(