A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
In my case, it was an Excel add-in named "MySQL for Excel" which is published by Oracle. I discovered this by:
- Run Excel
- File > Options > Add-ins
- Set "Manage" to "COM Add-ins"
- Choose Go
- Write down which add-ins are selected, uncheck them all, choose OK.
- Test if it's fixed.
In my case, it was fixed, so I repeated the above enabling one at a time until I discovered which add-in was causing the extra window to open.