Sometimes you keep opening a sheet that you have on your computer and every time it opens it launches in Protected View.
If you’ve tried going to File > Options > Trust Center > Trust Center Settings > Protected View > and disabling everything, you shouldn’t. Make sure those all say “Enabled” for security, otherwise you’re just opening your computer up to an attack, which may have been the entire plan.
Instead, Close the Workbook, Right-click on the Excel Document, click on Properties, then on the bottom of the General Tab you will probably see an extra “Security” line you have never seen before that reads “This file came from another computer and might be blocked to help protect this computer.” If this is your fie and you trust it completely, just click on “Unblock” and click “Apply”. Once you’ve done this the first time, you will never see that security line in the bottom of the General Tab of the Properties Dialog Box again.