Once installed, the add-in adds two buttons to the Classic Outlook for Windows compose toolbar: Attach with Files.com and Convert to Share Link. The buttons are available when composing a new message, or when a reply or forward is opened as a separate window. They do not appear when composing inline in the reading pane. Both buttons upload the files to Files.com, create a Snapshot Share Link, and deliver access through a link. Depending on the site's access-control setting, the link appears in the message body or in separate invitation emails. Files converted by the add-in are not sent as regular email attachments.

Required Permissions

Any user signed in to the Files.com Desktop App can use the add-in, provided their account has at least one folder with sharing permissions enabled.

Site Administrators, Workspace Administrators, and Folder Administrators always meet this requirement. Other users need at least one folder on their account with share permissions explicitly granted. Share Links created by the add-in are owned by the user who created them. If a user does not have any folder with sharing permissions, the add-in cannot generate a Share Link and will return an error.

Ribbon Actions

When you open a standalone compose window, two Files.com buttons appear in the Message tab, to the right of the standard Outlook toolbar buttons:

Attach with Files.com opens a file picker, uploads the selected files to Files.com, and inserts a Share Link into the message body.

Convert to Share Link takes files shown in the attachment bar of the message, uploads them to Files.com, replaces the attachments with a Share Link, and removes the original attachments. Inline images and videos embedded directly in the message body are not affected.

When forwarding an email that already has attachments, only attachments you add to the forward can be converted. Attachments carried over from the original message cannot be converted. To send those as Share Links, save them to your local disk first, remove them from the forward, then use Attach with Files.com to re-upload them.

Profile Selection

If your Desktop App has only one signed-in profile, the add-in uses it automatically. If you are signed in to multiple Files.com sites, the add-in prompts you to choose which site to use for the upload and Share Link.

The add-in creates Snapshot Share Links. When you use the add-in, Files.com takes a copy of each file as it exists at that moment and stores it in a hidden, read-only area of your site. The shared version is frozen when the link is created. Later changes to or deletion of the original file do not change the snapshot. Recipients can download the file but cannot upload or make any modifications through the Share Link.

The Snapshot copy is stored in your site's underscore folder and counts toward your site's storage usage. It is automatically deleted when the Share Link expires. Snapshot Share Links have a maximum expiration window of 60 days.

Site-wide sharing requirements apply to links created by the add-in. Access Control and Security explains passwords, email-based one-time passwords, recipient restrictions, expiration dates, publish dates, and visitor limits. Registration settings control the visitor information and acceptance of terms required before access.

The add-in prompts you for input only when site policy requires it, such as when a password or note is mandatory.

If your Site Administrator has disabled Snapshot Share Links, the add-in cannot create Share Links. Contact your Site Administrator if you encounter an error when using the add-in.

How Recipients Access the File

The Enforce Access Control for All Share Links setting for your site changes how recipients access the files you send.

If it is not enabled, a single Share Link is inserted into the message body. Any recipient who receives the email can open it. You can still apply recipient restrictions on individual links.

If it is enabled, the add-in does not insert a link into the message body. Instead, once you send your email, Files.com automatically sends each recipient their own personalized invitation URL in a separate email, using the recipients in the To, CC, and BCC fields. Each invitation URL binds to the first browser that opens it. This limits use across browsers but does not verify that the person opening it is the intended recipient. See Access Control for forwarding and replacement-invitation behavior. Note that recipients with blocked email domains will not receive an invitation.

In both cases, the recipient clicks the link and it opens a download page in their browser.

Because the add-in sends a link rather than an attachment, you can revoke access at any time after sending. Revoking the link prevents further access through it, even if the URL is still in the recipient's inbox. It does not remove copies the recipient already downloaded.

The Share Link Access Log records access activity. The visitor identity available in the log depends on registration and access-control settings. To confirm which recipients received an invitation email, check the Outbound Emails log.

Blocked Recipient Domains

If your site has Recipient Email Restrictions configured (for example, blocking free email providers or specific domains) and Enforce Access Control is also enabled, the add-in still generates the Share Link and sends the email. However, invitation URLs are only sent to recipients whose email domains are allowed. Recipients with blocked domains do not receive an invitation and cannot access the file.

The sender does not see any warning or error in Outlook. If you need to confirm which recipients received an invitation, check the Outbound Emails log after sending.

Troubleshooting the Add-In

The add-in works through the Files.com Desktop App rather than reaching your site on its own. If the Desktop App is not running or is not signed in, the add-in shows a warning and stops without uploading anything. Start the Desktop App and sign in to the site you want to use, then try the action again.

If the Files.com buttons are missing from the compose toolbar, restart Outlook. Outlook loads add-ins only while it is starting up, so a Desktop App installation or update that landed while Outlook was already running does not reach the toolbar until Outlook starts again.

The add-in keeps its own log at %TEMP%\FilesOutlookAddIn.log, recording load failures, button errors, and failures reaching the Desktop App. Send this file to our Support Team for any add-in problem. Send the Desktop App's own logs with it, because the two cover different halves of the work. The add-in's log stops at the point it hands a request to the Desktop App, and the Desktop App's logs pick up the upload and Share Link creation from there.

Using the Add-In