I am getting (attached) pop-up while trying to save the file.
Though this is not affecting my work since the warning pops up every time I save the it's annoying.
I have experienced a similar error in the past where I have unchecked an options in the Trust Center settings tab of Options dialog box.
Go to Excel Options, Select Trust Center, click on Trust Center Settings
Now select Priacy options and uncheck the checkbox Remove Personal informaiton from the file properties on Save.