It is critical to know which version you have installed, so you can choose and install the correct Outlook add-ons or plug-ins.

Most of the new computers sold on the market today, will be delivered with Windows 10 64bit. One of the big reason why computers are delivered with 64 bit, is that only 64-bit systems can address more than 4GB of RAM, so this one reason alone is why most people choose one over the other. There are many other reason why to chose 64 bit over 32 bit, when talking about the operating system, but in this blog we will concentrate on Outlook 32 or 64 bit.

Scroll down if you want to know, how you can check which version you are running.

The big question, should you run Outlook 32 bit or 64 bit?

By default Office 2016 and Office 365 installs the 32 bit version on new installs.

We strongly recommends the 32 bit version of Microsoft Outlook on computers that are running both 32-bit and 64-bit Windows, it is much more common than 64-bit Outlook.


So why do we recommend 32 bit?

With Outlook 64 bit there can be issues with plug-ins and backward compatibility, that´s why Microsoft still recommends installing the 32-bit version of Office. Most computers today have standalone Office application which only run 32 bit, these application wont be able to run if you have Outlook 64 bit installed.

Older add-ons such as the Calendar Printing Assistant is only compatible with the 32-bit Outlook.

By the way, if you are having issues running Calendar Printing Assistant on 64bit Outlook or with Office 2016, then have a look at Outlook Calendar Print.



You can’t install 64 bit versions of Office side-by-side with 32 bit versions Office.

The only reason to install Office 64 bit is:

  • You’re working with large data sets in Excel.
  • You’re working with files over 2GB in Project.
  • You’re working with extremely large pictures, videos, or animations in PowerPoint.

But remember Outlook 64 bit can give you many issues if you have third party Outlook add-ons or plug-ins.

You can read more about 32 vs. 64 bit Outlook in this link.


What version of Outlook am I using?

If you have Outlook 2007 then you have 32-bit Outlook.  Outlook 2007 only comes in a 32-bit package.

To check if you are using the 32-bit or 64-bit version of Outlook follow these 2 steps:

  1. Click Files
  2. Click Office Account
  3. Click About Outlook
  4. Read the version in the end of the first line.

The above steps is for Outlook 2016, but the steps are almost identical in older version of Outlook.

32 bit 64 bit Outlook