Office for Windows comes in two flavors called Click to Run (CtR) or MSI here’s how to tell which one you have and why it, sometimes, matters. We’ll also explain the two terms.
Which Office install you have (Click-to-Run or MSI) should not matter but occasionally a support page or person might ask you. Here’s how to tell …
Go to File | Account (Office Account in Outlook) then look at the About … section at bottom right. After the build number it should say either ‘Click-to-Run’ or nothing.
Click-to-Run or CtR
If there’s nothing after the Build number, it’s an MSI install.
It should say ‘MSI’ since that’s the term Microsoft itself uses to describe this type of install!
32-bit vs 64-bit
Click on the About … button to see the About window. It shows the version and build (as a combined number) and if it’s 32-bit or 64 bit. But NO mention of Click-to-Run and MSI.
Maybe, one of these days, Microsoft will present all the relevant details of an Office install on one screen instead of spread across various places. On that happy day, pink elephants will be flying our skies. Sigh.
What’s the difference Click to Run vs MSI?
Office for Windows is the same software whether it’s Click to Run (CtR) or .MSI.
The difference is how Office is installed and updated.
Click to Run (CtR) is the newer and mostly better way to install Office. Microsoft Office 365 for Windows installations are CtR, that’s the default and it was the only option for some time.
Office 2019, Office 2021 and Office LTSC are also Click to Run installs.
CtR downloads a small install program to run. That little program then downloads all the parts it needs to load Office onto your computer.
There is an ‘offline installer’ option which downloads everything you need in a single file then uses CtR technology to install Office. Office 365 offline install, get the full download
MSI is one big download (was around 3.5GB for Office 365) which contains both the installer program and all the Office components. Once it’s downloaded, run the file and Office will install.
A ‘Click to Run’ Office is updated more seamlessly than updating a .MSI version. There should be less need to restart Office programs with a CtR installation.
MSI is now only used for older versions of Office. Some Office 2016 and earlier versions of Office.
Why ‘Click to Run’?
The name ‘Click to Run’ might seem strange since it’s hardly that simple. The name is a hangover from the original way the CtR streaming installer worked.
Some Office users might remember the original ‘Click to Run’ streaming install that was very slick. It installed the basic parts of Office first so you could start using Word, Excel etc very quickly. As people worked with Office, the rest of the program was quietly installed in the background. If you clicked on a component not ready (e.g. WordArt or Equation Editor), CtR would prioritize that so it was soon ready. This streamed ‘Click to Run’ install wasn’t truly faster (despite Microsoft’s hype saying otherwise), but it let people start working more quickly.
The streaming part of ‘Click to Run’ was quietly dropped by Microsoft but the name remains.
These days you have to wait until Office is fully installed by ‘Click to Run’.
Why was the streaming install dropped? Streaming CtR had problems, it was expensive to maintain, and customers weren’t fooled by Microsoft’s promises of a faster install. Redmond appears to have dropped the streaming element of CtR in favour of a less flashy but more stable installation.
Originally it was called a MicroSoft Installer with .MSI files, it’s now called Windows Installer but the MSI name/extension remains.
Windows programs can be installed from .MSI files. That’s what an ‘MSI’ Office install does even though there’s no direct MSI download..
.MSI files contain the program, other files and settings needed to install and run the program. Double-clicking a .MSI file will install the contents. You’ve probably installed a program, patch or update from an .MSI file.
For most programs, including Office, that .MSI container is inside the big Office install download (a .exe or .img disk image). In the ‘olden days’ of CD/DVD installations there were MSI files on the disk.
Office 2013, Office 2010, Office 2007
Office 2013 and earlier are only .MSI installations. Any installation from a CD, DVD or disk image is an .MSI install.
Office for Mac
The whole MSI / Click to Run issue is a Windows installation thing. It doesn’t apply to Office for Mac which is installed quite differently.