I have Inspiron 7380 just a few months.  In recent months, I'd get notification about update and when I clicked "Install", nothing happened.  So I manually opened Dell Update, it scanned and found N updates. For example, today there were two updates identified.  I clicked "Install" and then the following is displayed:

"Installation Complete

0 of 2 successful"

I have no ideas if the updates were installed or not.