I have an add-in that adds two custom sub-menus (using the CommandBar control) to the right-click on a spreadsheet. These menus link directly to other macros and add-ins.

I have discovered that when Excel is closed after each use, it adds (the same) two lines to the Excel15.xlb file in C:\Users\*username*\AppData\Roaming\Microsoft\Excel, which is causing the xlb file to become very bloated - it was nearly 30mb when I discovered it which, I assume, is responsible for Excel being incredibly sluggish on start up even in a blank workbook.

So my question is, how can this behaviour of an ever increasing file size be prevented?

Thanks in advance.