Problem solved. After 48 hours, SupportAssist still claimed to be "Installing" the BIOS update. I checked that the BIOS had not been changed (Windows+R, and typed “msinfo32” into the Run box), then closed SupportAssist. I downloaded the BIOS update file from www.dell.com/support/home/au/en/audhs1/drivers/driversdetails?driverid=v9678 and double-clicked the file to run it, and it updated the BIOS successfully.
I have a Dell Inspiron 15 3565 running Windows 10 and Norton antivirus (both up to date). Dell SupportAssist recommended an *Urgent* "Dell Inspiron 3465/3565 System BIOS" update (to version 1.10.1) and a *Recommended* Bluetooth driver update. I now realise that I should have downloaded the BIOS update file and done a manual update, but I clicked "Install" in SupportAssist. The Bluetooth update installed successfully, but after 12 hours the BIOS update status still says "Installing...". There is no BIOS update box hiding behind the SupportAssist screen. I cannot select "Cancel" in SupportAssist as the button is greyed out and the cursor changes to a stop sign. Given that this is a BIOS update, I am very reluctant to kill SupportAssist with Task Manager or to reboot. What should I do? Please help!
Inspiron 3565 BIOS update still "Installing" after 12 hours