Something to keep in mind, too: Older versions of Office might not be able to open files created with newer versions of Office. If you insist on running more than one version of Office, here are some steps you can take to minimize problems you’ll run into. Keep in mind that the 32-bit version of Office can run on either the 32-bit or 64-bit versions of Windows.  Also, Microsoft Office may install as 32-bit by default, unless you already have a 64-bit version of Office on your computer, so Microsoft is a great resource for how to opt for the 64-bit version instead, or how to decide which is best for you in general. The reason for this is that each installation involves a bunch of moving parts. Each has a specific way its shared programs, registry keys, file extensions, and other specifics are handled. The same holds for Office programs that are purchased separately or that require unique installation. For example, you might purchase Microsoft Project or Microsoft Visio separately. Earlier versions should still be installed before later versions, across the board. You will be prompted to either select Keep These Programs or Remove Previous Versions.  Other programs in the Microsoft Office suite may give you problems as well. Some users report issues when installing multiple versions of Microsoft Access, for example. If you do run into a situation where some programs install correctly and others don’t, consider uninstalling one of the multiple versions of that program if possible. Depending on how your suite is packaged, you may or may not be able to do this on your own. In those cases, you can either go back to using just one version of Office or reach out to Microsoft for additional perspective. If you Insert - OLE Objects into a document, those objects will be formatted according to the most recent version of Office installed on your computer, regardless of which version you are working in. This means problems may ensue if you are sharing files with others who have different versions of Office than yours, for example.