Deploy the Part3 add-in on on-premises Exchange (IT admins)

The Part3 add-in for Outlook lets your team file project emails straight from Outlook into the right Part3 project, with their attachments. This article is for the Exchange administrator at a firm whose mailboxes are hosted on its own Exchange Server (on-premises).

If your mailboxes are in Microsoft 365 (Exchange Online), including hybrid setups where the mailboxes have moved to the cloud, follow Deploy the Part3 add-in for Outlook (IT admins) instead.

In this article, we'll cover:

• What to do before you start
• Supported versions of Exchange and Outlook
• How to deploy the add-in
• How long it takes to appear
• Updates and what to do
• Change who has it, or remove it
• Network and size limits
• Troubleshooting

Before you start

• Exchange Server Subscription Edition (SE). See Supported versions below.
• Classic Outlook for Windows from Microsoft 365 Apps on your users' computers. Older one-time-purchase versions of Outlook can't file emails.
• An admin who can install organization add-ins. You need the Organization Management role in Exchange.
• Email filing turned on for your Part3 organization. Contact your Part3 contact or support@part3.io to turn it on. Your Part3 organization admin then chooses which projects take emails; see Choose which projects take filed emails (organization admins).
• Part3 accounts for your users. Each person signs in to the add-in with their own Part3 account. They can file only to projects that your firm owns in Part3 and that they are a member of.

Supported versions of Exchange and Outlook

Where Outlook is too old to file, the button still shows. The Part3 pane then says This version of Outlook can't file emails to Part3 instead of filing.

The add-in shows when reading email. It doesn't appear while you write one.

Deploy the add-in

The on-premises add-in has its own manifest:

https://outlook.part3.io/manifest-onprem.xml   

Use this one, not the Microsoft 365 manifest. Exchange Server refuses the Microsoft 365 manifest.

Option A: Exchange admin center

Step 1: Sign in to the Exchange admin center (EAC) and go to Organization → Add-ins.

Step 2: Select + (New), then Add from URL, and paste the manifest link above. Select Install.

Step 3: Select Part3 in the list, then Edit. Turn on Make this add-in available to users in your organization, and choose Optional, enabled by default or Mandatory, always enabled. Select Save.

Option B: Exchange Management Shell

To install it for everyone:

New-App -OrganizationApp -Url "https://outlook.part3.io/manifest-onprem.xml" -DefaultStateForUser Enabled -ProvidedTo Everyone   

To start with a pilot group, use -ProvidedTo SpecificUsers -UserList "user1@yourfirm.com","user2@yourfirm.com"    instead of -ProvidedTo Everyone    .

The add-in asks for the same Read/write mailbox permission as on Microsoft 365, for the same reasons. See What the add-in's permission is used for.

How long it takes to appear

Outlook picks up new add-ins when it starts. Ask users to fully close and reopen Outlook. The add-in's button is File to Part3, in the Part3 group of the ribbon when an email is open or selected.

Updates

• Most updates are automatic. Part3 hosts the add-in, so improvements and fixes reach your users without any action from you.
• Occasionally the manifest changes, for example a new button or capability. Exchange Server doesn't download the new manifest by itself. When Part3 tells you the manifest changed, remove the add-in and install it again from the same link.

Change who has it, or remove it

• In the EAC: go to Organization → Add-ins, select Part3, then Edit to change who has it, or Delete to remove it.
• In the shell: find the add-in with Get-App -OrganizationApp | Where-Object DisplayName -eq "Part3"    , then use Set-App    to change who has it or Remove-App -OrganizationApp    to remove it.

Removing the add-in doesn't remove anything from Part3. Emails already filed stay in their projects. The Filed to Part3 category stays in users' mailboxes until they delete it.

Network and size limits

• Network. Your users' computers need the same addresses as Microsoft 365 customers. See Network allowlist. Part3 never connects to your Exchange Server; the add-in works inside Outlook on each computer.
• Attachment size. Part3 accepts attachments up to 150 MB each, but Exchange Server's message size limit applies first. Its default is 10 MB per message.

Troubleshooting

Q: Exchange says the add-in's API version isn't supported.

You used the Microsoft 365 manifest (manifest.xml    ). Install manifest-onprem.xml    instead.

Q: Users don't see File to Part3, or Outlook says there are no add-ins.

Check that the add-in is enabled for them in the EAC, then have them restart Outlook. Outlook loads add-ins through Exchange Web Services (EWS); if EWS isn't working for that mailbox, no add-ins appear at all. Check that other add-ins load, and that the EWS virtual directory is healthy.

Q: The pane says "This version of Outlook can't file emails to Part3."

That computer's Outlook is too old. Use classic Outlook for Windows from Microsoft 365 Apps, kept up to date.

Q: Can users file from Outlook on the web?

Not when it's served by your own Exchange Server. Use classic Outlook for Windows.

For everything else, see the troubleshooting section of File emails to Part3 from Outlook.