After upgrading to office 2016, I now have a list of "Recent Items" under the attachment button. I want to turn it off because I never attach recent items and always need to browse to a specific location for a file.
Outlook doesn't have an option to change the number of recent files but you can set a value in the registry. Setting it to 0 will remove all recent items from the Attach File menu, leaving only the Browse location folders.
You'll need to restart Outlook after setting the MaxAttachmentMenuItems value.
Delete the MaxAttachmentMenuItems value from the registry to reset it to the default value of 12. The maximum value is 20 but more than 14 items is likely to need scroll bars.
You'll need to add the DWORD MaxAttachmentMenuItems to the registry.
Key: HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Options\Mail
DWORD: MaxAttachmentMenuItems
Decimal value: 0 to 20.
Ready-to-use registry file: 0 MaxAttachmentMenuItems
To use this file, right click on it and choose Save Link as (Chrome) or Save Target as (Internet Explorer and Edge). After it's saved, double click to run it, OKing the dialogs (3 or 4) that come up. If you want to see what's in the *.reg file, open it in Notepad (right click on .reg files, choose Edit then OK the dialog to open it in Notepad).
More Information
Both Word and Excel have an option to control the number of recent files you see on the Open sidebar. Look for the option in those programs at File, Options, Advanced. Show this number of Recent Documents is under the Display section.
Published April 22, 2016. Last updated on April 22, 2016.