If you are trying to attach OneDrive files in Outlook on the Web see this article instead: https://support.pinnacletechnology.solutions/en/support/solutions/articles/4000195141-attach-onedrive-file-in-outlook-on-the-web


To attach OneDrive files in Outlook Desktop do the following:

  1. Create a new email as usual
  2. Select Attachments
  3. Click "Browse Web Locations"
  4. Click "OneOne - [Company name]", you should also see your email address as a part of this option
  5. Once you've clicked that a new file explorer window will open and you can attach any files from OneDrive you want