Facing issue while closing the Excel file : Even though nobody is working in that file.

Based on the image you shared, I’m guessing that your Excel file is located on a network drive.

It’s considered a good practice to avoid working on network locations as much as possible, normally this is achieved by making a copy of the file at the start of the process, moving that copy to a local folder like C:\Users\<YourUserName>\Appdata\Local\Temp\ (%TMP% \ $Env:Tmp), and working on that copy instead. 

Once the process is completed, you can overwrite the original file with the local copy.

Besides that, I’d suggest using the Excel Basic package by default, and only use the Excel Advanced package when absolutely necessary.