OK, let’s say you already installed v2, whether inadvertently or…  advertently.

And now you need to downgrade to v1, so that your workbooks function on your server, or can be opened by other people running v1 on their desktops.

So… how to do that?

The Obvious Thing Works for Most People

Simple:  just uninstall v2 (from Windows Control Panel) and then install v1.

But if you see this error when you try to build a new workbook, or open an old one, well, it’s not working out:

An operation that uses the database driver could not be completed - seen after downgrading PowerPivot v2 to v1.

What to do if you get that error?

1) Open Start Menu

2) Find “Command Prompt” – it is under Accessories

3) Right Click on Command Prompt, choose Run as Administrator

4) Once in the cmd window (looks like the old DOS window), type the following:

regsvr32 “C:\Program Files\Microsoft Analysis Services\AS OLEDB\10\msolap100.dll”

You may need to correct for your actual folder location – that’s the location on my machine.  The quotes ARE required.