For Admins and IT Teams
For organizations that prefer to sideload or manually deploy the current production version of ExtendSync for Outlook, follow the steps below.
📘 READ ME FIRST
Although sideloading is available, we recommend installing the ExtendSync add-in from the Microsoft Office Store or via Centralized Deployment for automatic updates and easier management.
To stay up to date with the latest manifest file and sideload instructions, regularly monitor the Release Notes for any updates or changes.
Installing the Production Add-in
Installing or reinstalling the production add-in involves removing any existing version (such as an older or preview build) and then adding the latest production version using the manifest file URL.
Step 1: Remove the Existing Version
Before installing or redeploying the production version, uninstall any previously installed add-in (e.g., an older build or preview release).
You can always reinstall the latest production version later from the Microsoft Office Store.
Go to https://aka.ms/olksideload, and the Add-Ins for Outlook window will open.
Select My Add-Ins.
Locate the old or preview versions of ExtendSync add-in, click
...in the lower-right corner of the add-in tile, and select Remove.
Reference: Microsoft Article - Delete add-in from Outlook
Step 2: Install the Production Version using Manifest File
ExtendSync Outlook Manifest URL: https://manifests.ceol.cloudextend.app/olns-production.xml
Download the file from URL: https://manifests.ceol.cloudextend.app/olns-production.xml
From the Add-ins for Outlook screen, select My Add-Ins.
Scroll down to Add a Custom Add-in → choose Add from File.
Note: The Add from URL option is no longer available to install a custom Outlook add-in. As a workaround, open the URL in your preferred browser to download the add-in file, then use the Add from File option to install it.
A warning prompt will appear. Click Install and wait for the installation to complete.
✅ You’ve now successfully installed the CloudExtend ExtendSync for Outlook Production Add-in.
➡️ Reference: Microsoft Article - Install Custom Add-Ins
Removing Older or Test Versions
If your organization previously installed a preview or test version of the add-in, it’s best to remove it to avoid conflicts.
Follow the same steps under Remove the Existing Version, but select the Preview or Test Add-in instead of the production one.
Centralized Deployment
If you plan to deploy ExtendSync organization-wide, use Centralized Deployment via the Microsoft 365 Admin Center.
This approach ensures:
Automatic updates across all users
Simplified version management
Centralized permission control
Still Having Trouble?
We’re here to help!
💬 Chat with us — Click the chat icon at the bottom-right of this page.
📧 Email: cloudextend-support@celigo.com
Please include:
Your NetSuite role name
A screenshot of the error (if available)
Steps you’ve already tried