Startup Folders

xlStart Directories

There are two folder locations which are Always Checked as well as an Optional Alternative startup folder if you need it.
These directories can be used to store workbooks that you always want open as well as global templates.
Any templates (or workbooks) that you save in any of these folder locations will be opened automatically when Excel starts.
If there are any workbooks in any of these folders then the blank default workbook will not be displayed.

xlStart - Personal folders

This is the first folder location that is checked.
Any file (with any file extension) will be opened.

Excel 365 - C:\Users\"user name"\AppData\Roaming\Microsoft\Excel\XLStart\ 
Excel 2021 - C:\Users\"user name"\AppData\Roaming\Microsoft\Excel\XLStart\ 
Excel 2019 - C:\Users\"user name"\AppData\Roaming\Microsoft\Excel\XLStart\ 
Excel 2016 - C:\Users\"user name"\AppData\Roaming\Microsoft\Excel\XLStart\ 

xlStart - Machine Folders

This is the second folder location that is checked.
The exact locations of the xlstart folders will depend on which version of Excel you are using.

Excel 365 - C:\Program Files\Microsoft Office\root\Office16\XLStart\ 
Excel 2021 - C:\Program Files\Microsoft Office\root\Office15\XLStart\ 
Excel 2019 - C:\Program Files(x86)\Microsoft Office\root\Office15\XLStart\ 
Excel 2016 - C:\Program Files(x86)\Microsoft Office\Office16\XLStart\ 

Excel cannot open two workbooks with the same name at the same location.
If there is a file with the same name already open then you will see a prompt to let you know the file will not be opened.

Alternative Startup Folder

This is the third folder location that is checked.
You cannot change any of the above folder locations but it is possible to use another folder as a startup directory.
This is a directory that can be used either as an alternative or as an Additional Startup Folder.
If you want to load specific workbooks or add-ins when Excel starts up you can use this folder instead.
Select (File > Options)(Advanced tab, General) and copy and paste your folder into the "At startup, open all files in" textbox.

Personal.xlsb

This is called the Personal Macro Workbook and is a good place to store your common macros.
For more details about this special workbook, please refer to the Macros > Personal.xlsb page.

Important

The alternative startup location is often used to store custom add-ins or a workspace file that you will always want available or open every time you start Excel.
You can also save a workspace file into this folder if you want to open multiple workbooks automatically when Excel starts.