I'm running Solidworks and I have ABC.xlsx open in Excel.
In Solidworks, I open my configuration Design Table to change some values. Excel disappears! It also disappears from the Windows taskbar. It's still running in Task Manager though.
I close the Design Table, and Excel remains hidden.
I know it's still running because when I go Start-->Restart computer, then I got a dialog asking if I want to save changes to ABC.xlsx .