Outlook: Pdf Preview Handler Error

For my user, they had not opened Adobe Reader yet. Opening it and agreeing to all the licensing resolved the issue.

Open the registry editor, search for "OutlookSecureTempFolder" copy the Value data and paste it on the explorer url bar + Enter, and highlight and delete all items in this folder

Disabling Internet Auto Detect did the trick for me.
For example, on...

• Windows 10 64 bits
• Adobe Acrobat Pro or Adobe Reader DC
• Outlook 2016 (32bits)

...do the following:

Open Adobe Reader -> Go to Edit menu -> Preferences -> Click Internet -> then Internet Settings -> Click LAN Settings -> Uncheck the box -> “Automatically detect settings" -> Click OK button and close Adobe

Check Adobe Reader compatibility mode; if you use Office 2016 and an OS like Windows Server 2016 or Windows 10, then select "Run this program in compatibility mode for - Windows 8".

Solution:

Open Adobe Reader X or XI etc ... on Menu > Edit > Preferences > General > Click Select "Default PDF Handler" at the bottom of the screen > Click Apply on the popup > OK.

Good luck!

In my case, I was using Adobe Reader, but the install was new and I hadn't yet opened Reader directly to accept the EULA. Once I had done that, the preview in Outlook worked.

I had the same problem while using Acrobat Pro and Outlook 365. .pdf handler issue. My solution, close outlook, download Adobe Reader DC, then re-do a file association with Acrobat Pro to open the .pdf. File handler icon changed to Reader and opens in Acrobat Pro.