Blank window opens on startup along with normal window

[cbrown6305]

I've customized a template for new files and placed it in the XLSTART folder as "Book.xltx". Now whenever I open an excel file from windows explorer, excel launches that file and a blank window. If I navigate to the blank window and close it, the file that I opened from explorer closes as well. I've figured out a workaround to close the blank window by navigating to it, opening a new blank sheet in that window, then closing the window. If I perform that series of actions, the blank window will close leaving the file that I launched from explorer open. This is super annoying to have to execute every time I open an excel file from the explorer. Any ideas as to how I can keep my Book.xltx template in tact, but stop this blank window from opening?

Also (FYI), I have .xlsb book in the startup folder that houses my custom macros and is hidden. That book as been there before this issue started.