Unable to save (overwrite) an installed pdf document instead of saving as.

I have recently had an extremely provocative issue where Acrobat Reader would prompt me to save as a document installed on my machine instead of overwriting the original file upon clicking ctrl+s. I started looking for the cause of this issue, and upon tinkering with the settings, I finally solved it. I went to Preferences > Security (Enhanced) and unchecked “Enable Protected Mode at startup”.