Deploying Microsoft Office to thirty machines sounds straightforward. It isn’t. You end up with different app sets on different desks, update prompts nobody approved, and users calling IT because something’s missing. That’s the problem the Office Customization Tool was built around.
OCT isn’t for single-laptop setups. It’s for anyone managing Office at scale: IT teams, admins, and small business owners who don’t want to click through the same installer twenty times and get twenty different results.
What Is the Office Customization Tool?
Microsoft built OCT to handle Office deployments at the configuration level. Before anything installs, you set which apps go on machines, which don’t, what languages ship with them, how updates come in, and how licensing gets handled.
It doesn’t spit out a modified installer. It creates an XML file. That file tells the Office Deployment Tool what to do when the actual installation runs. OCT is the form. ODT carries out the instructions.
You open it at config.office.com. Nothing to download or install. Microsoft maintains it on their end, so what you see always reflects current supported products.
What Can You Actually Configure?
OCT breaks into several panels. Each one controls a different part of the deployment.
Products and releases: Pick the Microsoft 365 Apps edition that matches your license. Choose the full suite or strip it down. If your team doesn’t use Access or Publisher, cut them. Fewer apps mean a smaller install and less to maintain. You also choose between 32-bit and 64-bit here.
Update channel: This controls how often devices get feature updates. The current channel pushes updates monthly. The monthly enterprise channel does too, but with a short delay for stability testing. Semi-annual enterprise channel updates are twice a year. Most IT teams running managed environments go semi-annually.
Language: Add your primary language and any secondary ones. Set a fallback so Office doesn’t fail silently if someone’s preferred language isn’t available.
Installation settings: Run silent installs with no prompts. Suppress the restart dialog. Choose whether to pull existing Office versions off machines before installing.
Licensing and activation: Set up KMS, MAK, or user-based licensing tied to Microsoft 365 accounts. Get this wrong, and you’ll spend an afternoon troubleshooting “Unlicensed Product” errors.
Application preferences: Pre-configure app-level settings. Disable macros by default. Turn off specific add-ins. Adjust telemetry. This panel saves a lot of post-deployment cleanup.
How to Use the Office Customization Tool: Step by Step
Step 1: Open the Tool
Go to config.office.com. Sign in with a Microsoft account if it asks. You’ll land on a blank configuration ready to fill out.
Step 2: Choose Your Architecture and Suite
Under Products, select your Microsoft 365 Apps edition. Go 64-bit unless you’re running legacy COM add-ins that only support 32-bit. Most modern environments don’t need 32-bit anymore.
Step 3: Exclude Apps You Don’t Need
OCT includes everything by default. Go through the app list and cut what your team won’t use. It keeps the install lean and reduces the number of things that need updating later.
Step 4: Set the Update Channel
Match this to how your IT team handles patching. The monthly enterprise channel gives you predictable timing. The current channel gets you the latest features faster. Semiannual is the safe choice for environments where stability takes priority.
Step 5: Configure Language Settings
Add your main language first, then any secondaries. If your organization spans multiple regions, do this now. Asking users to install language packs manually after the fact creates a support headache.
Step 6: Set Installation Behavior
Toggle silent installation on if you don’t want users seeing prompts mid-install. You can also suppress the restart notification if that suits your rollout plan.
Step 7: Export the Configuration File
Hit Export in the top right. OCT downloads a file called configuration. XML. That file goes into your deployment workflow. For a detailed look at what an effective configuration looks like, this breakdown of the Office customization tool covers the finer points well.
How OCT Works With the Office Deployment Tool
OCT builds the plan. The Office Deployment Tool runs it.
Download ODT from Microsoft’s site. It extracts as a setup.exe with some sample XML files alongside it. Put your configuration.xml in the same folder.
Run this first to pull the Office installation files:
| setup.exe /download configuration.xml |
Once that finishes, run the install:
| setup.exe /configure configuration.xml |
That’s it. If you set the install to silent, users won’t see anything. The result is the same Office setup on every machine: same apps, same update channel, same language. Machine two looks like machine two hundred.
Common Issues and How to Fix Them
The XML file throws an error on deployment. Nine times out of ten, this comes from manual edits after export. A missing bracket or a mismatched tag breaks everything. If you’ve touched the file after downloading it, open it in a text editor and check the structure carefully before running again.
Office installs but shows “Unlicensed Product.” Go back to the Licensing section in OCT. The activation method in your configuration needs to match your actual licensing model. Fix it, re-export, and redeploy.
Users are getting update prompts that nobody approved. Your update channel is probably set to the current channel. That pulls updates as Microsoft releases them. Switch to Monthly Enterprise or Semi-Annual, update the config, and push it out again.
64-bit Office is breaking an older add-in. Some legacy add-ins, older COM-based tools especially, only work with 32-bit Office. If you’re seeing crashes or missing features after deployment, regenerate the configuration with 32-bit selected.
OCT vs. Manual Installation: Why It Matters at Scale
One machine? The standard installer is fine. Click through, pick your apps, done.
Fifty machines? That’s where things fall apart. Someone skips a language pack. Someone else leaves OneDrive out. One machine updates ahead of the rest because a user clicked the wrong thing. Now you have fifty slightly different setups and no easy way to know what’s on what.
OCT fixes that. Every machine is built from the same configuration. XML comes out identical. Same apps. Same update behavior. Same preferences. Whether it’s machine five or machine five hundred.
For teams running Microsoft Intune or SCCM, OCT configurations drop into those pipelines directly. It stops being a one-time setup and starts being part of how you manage devices long-term.
Conclusion
OCT feels optional until you actually need it. Then it becomes the thing you wonder how you managed without.
If you’re handling more than a handful of Office installs, building around a configuration file removes the inconsistency. Fewer support calls. Fewer surprises after an update. Deployments you can repeat without second-guessing what ended up on each machine.
The setup takes fifteen minutes. The payoff is a consistent environment across every device you manage.
Frequently Asked Questions
What is the Office Customization Tool used for?
It’s a Microsoft web tool that lets admins build an XML configuration file before deploying Microsoft 365 Apps. You control which apps install, how updates work, which languages are included, and how devices activate. All before a single machine gets touched.
Do I need the Office Deployment Tool if I use OCT?
Yes. OCT creates the configuration file. ODT is what actually downloads and installs Office using that file. They’re separate tools built to work together.
Can I use OCT for Office 2019 or Office 2021, not just Microsoft 365?
OCT works best with Microsoft 365 Apps running Click-to-Run. For perpetual versions like Office 2019 or 2021, it can still generate a configuration, but don’t expect full parity. Update channel settings; for example, behave differently there.
Is the Office Customization Tool free?
Yes. It’s available at no cost at config.office.com. You need a valid Microsoft 365 license to deploy Office, but using OCT itself costs nothing.
What happens if I edit the configuration XML manually after exporting?
You can. Microsoft’s schema for Office deployment XML is documented. But any formatting error will break the deployment. If you edit the file manually, double-check it before running setup.