Excel 2007: Warnings about closing unsaved documents suddenly stopped appearing

Question

Microsoft

Hello!
I understand that the question is not quite typical for Habr and will seem too simple to someone, but I searched for help, settings and the Internet and could not solve the problem.
So, the point.
Suddenly, warnings about closing unsaved documents stopped appearing.
That is, they used to show up, but now they don't.
Perhaps automatic updates were installed, but at the time of writing the post there are no new uninstalled office updates.
Thanks in advance for any help!

Answer 1

stackoverflow.com/questions/8438746/excel-doesnt-prompt-to-save-unsaved-files-on-application-quit
They write that you need to disable the solver plugin, or in our opinion how is it? which solves optimization problems. "Search for a solution"!

Answer 2

Thank you all, plus in karma.
The problem was solved by rolling back to the last restore point (just the day before yesterday) and prohibiting MSO updates.