| .orderedtest |
Visual Studio Ordered Test File |
| .olk14note |
Outlook Note File |
| .olk14group |
Outlook Group File |
| .olk14event |
Outlook Calendar Event File |
| .olk14contact |
Outlook Contact File |
| .olk14signature |
Outlook Signature File |
| .olk14category |
Outlook Category File |
| .olk14mailaccount |
Outlook Mail Account File |
| .olk14msgsource |
Outlook Email Message Data File |
| .ofr |
OptimFROG Audio File |
| .oxps |
Open XML Paper Specification file |
| .opal |
Microsoft Office User Settings File |
| .olk14msgattach |
Outlook 2011 Email Message Attachment File |
| .olk15msgattach |
Outlook 2016 Email Message Attachment File |
| .olk14task |
Outlook Task File |
| .olk14pref |
Outlook Preferences File |
| .onetoc |
Microsoft OneNote Table of Contents File |
| .pps |
PowerPoint Slide Show |
| .ppt |
PowerPoint Presentation |
| .pkg |
Package File |
| .pptx |
PowerPoint Open XML Presentation |
| .prf |
Outlook Profile File |
| .pst |
Outlook Personal Information Store File |
| .pub |
Publisher Document |