If you tried to install a 64-bit or 32-bit version of the Office suite, or a standalone application such as Visio on a computer that already has either the 32-bit or 64-bit version of Office, you could see an error message similar to the one below. This occurs because you can't mix 64-bit and 32-bit versions of Office.
What to do
To fix this error and switch from 32-bit to 64-bit (or vice-versa), you must do the following in this order.
Go to Uninstall Office from a PC and follow the steps to uninstall the version of Office (or stand-alone Office application, such as Visio or Project) you don't want.
Install the 32-bit or 64-bit version of Office
Select your version below and follow the installation steps.
For overall guidance about which version to install, see Choose the 32-bit or 64-bit version of Office. If you're not sure which bit version you may have already installed, see What version of Office am I using?