From the above, you can see there are no error codes, just a link to go online for more help. The message will differ depending on the Office 365 edition you are trying to install. So how do you resolve this error?

The following products cannot be installed at the same time Office error

Based on the error message, intuitively, you’ll think the error is caused by a conflict of an already installed Office 365. But, alas, this isn’t the case. So don’t waste any time trying to find any remnant of a previous Office installation, chances are it is not there! This error is solely caused by older versions of the setup.exe file. So to fix this error; 1] IT administrators, can download the latest version of the Office Deployment Tool, and also the Office Customisation Tool for help with XML configuration files. Once you have the setup.exe, you can replace your older setup.exe. Then run setup.exe /download configuration.xml (or change the file name to whatever XML name you’re using). This downloads the files according to your configuration.xml file. Then you can run setup.exe /configure configuration.xml to install according to your configuration.xml file. 2] Consumers, simply click here to visit Office.com to download a fresh installer (setup.exe). That’s it, folks. Happy computing!