If Task Manager shows Microsoft Office Click-to-Run using a big chunk of your CPU, the cause is almost always one of three things: it is stuck partway through an update or repair, Windows has flagged your network as metered, or a broken add-in keeps making it retry. Each of these has a clear fix, and you do not need to delete anything to get your CPU back to normal.
Below is what this process actually does, how to tell which cause you are dealing with, and the fixes in the order worth trying, from the quickest to the most involved. Work top to bottom and stop as soon as the CPU calms down.
What is Click-to-Run, and why is it running?
Click-to-Run is the background service that installs, updates, and repairs your Office apps over the internet. You will see it in Task Manager as OfficeClickToRun.exe, listed under the service name Microsoft Office ClickToRun Service. It ships with Microsoft 365 and with retail versions of Office 2016, 2019, 2021, and 2024.
Instead of installing Office from a disc, Click-to-Run streams the apps to your PC and keeps them patched in the background. That is why it can show up even when no Word or Excel window is open. It handles security updates, feature updates, and the quick repairs that fix damaged files, so it is meant to keep running quietly. The trouble starts when it stops running quietly.
You might also spot a version labelled Microsoft Office Click-to-Run (SxS) in Task Manager. That is the same service doing side-by-side installation work, which lets a new Office build stage while the current one keeps running. Under normal conditions it uses a small slice of processor power and you would never notice it. When you do notice it, something in that update or repair cycle has gone wrong.
Key point: Click-to-Run using CPU is normal during an update. Click-to-Run using CPU for an hour with no end in sight is not.
Why is the CPU spiking?
High CPU from this process is rarely random. Before you start changing settings, match what you are seeing to the most likely cause. That way you fix the actual problem instead of working through every step for nothing.
| What you see | Likely cause | Quick test |
| A short spike, then it settles | A normal update downloading and installing | Wait 30 to 60 minutes and recheck |
| Steady high CPU that never drops | A stuck update or repair loop | Run a manual update, then a repair |
| High CPU only on some networks | Windows flagged the connection as metered | Turn off the metered setting |
| Spikes tied to opening Office | A broken or blocked add-in | Open the app in safe mode |
| The process is in the wrong folder | Malware using the name as a disguise | Check the file location and signature |
The single most common surprise cause is the metered connection flag. On a home Wi-Fi or a phone hotspot, Windows sometimes marks the connection as metered to save data. Office then gets confused about how to fetch updates and keeps retrying, which pins the CPU. It also explains why the same laptop can be fine at home and terrible on another network.
Confirm it is really Click-to-Run first
Before you change anything, make sure this process is the actual problem and not just a passenger. Press Ctrl + Shift + Esc to open Task Manager and look at the Processes tab. If Microsoft Office Click-to-Run is sitting above roughly 50 percent CPU, or high on disk, it is the one to chase.
Two quick tells sharpen the diagnosis. If the CPU climbs the moment you open Word, Excel, or Outlook, you likely have a stuck component or a bad add-in. If it spikes on a predictable schedule instead, a scheduled update task is probably retrying and failing. Note high disk use too, because high CPU paired with high disk usually means install or repair activity is running, not a real workload.
Is OfficeClickToRun.exe a virus?
In almost every case, no. It is a genuine Microsoft file. The real one lives in this folder:
C:\Program Files\Common Files\Microsoft Shared\ClickToRun\
Malware sometimes copies the name of a trusted process to hide, so a quick check is worth doing if the CPU use looks strange. In Task Manager, right-click the process and choose Open file location. If it opens the folder above, you are fine. Then right-click the file, open Properties, and check the Digital Signatures tab: a valid signature from Microsoft Corporation confirms it is real. If the file sits somewhere else, such as a temp folder, or has no Microsoft signature, run a full scan with your antivirus before touching anything.
How to fix Click-to-Run high CPU usage
Work through these in order. The first few solve it for most people, and none of them break Office. Try one, watch Task Manager for a minute, and move to the next only if the CPU stays high.
1. Wait it out, then restart the apps
If a real update is downloading, killing the process just delays it. Close all your Office apps, wait 30 to 60 minutes, and check again. If the CPU has dropped below about 5 percent, you are done.
If you cannot wait, save your work and force the apps to close. Press Ctrl + Shift + Esc to open Task Manager, select each open Office app, and click End task. Give it a minute, then reopen only what you need.
2. Turn off the metered connection
This is the fix that quietly solves it for a lot of people, and it takes ten seconds. You are telling Windows to stop treating your connection as data-limited so Office stops retrying its updates.
- Open Settings and go to Network & Internet.
- Select your active Wi-Fi or Ethernet connection.
- Find Metered connection and switch it off.
- Restart your PC, or restart the Click-to-Run service, then watch Task Manager.
If the CPU drops to normal within a few seconds of doing this, that was your cause. It is especially common on hotspots and on some wired setups that got flagged by mistake.
3. Update Office manually
A stuck automatic update can loop in the background and keep the CPU high. Forcing the update by hand often clears the jam. Keep the PC plugged in and connected while it runs.
- Open any Office app, such as Word, and select File.
- Click Account in the sidebar.
- Open the Update Options menu and choose Update Now.
- Let it finish, close the apps when prompted, then check Task Manager.
CPU can climb while the update installs, which is expected. It should settle once the patch is applied. If it never settles, move on to a repair.
4. Check for a broken add-in
If the CPU jumps whenever you open Office, a third-party add-in may be failing and forcing Click-to-Run to retry, especially just after an update. Safe mode loads Office without add-ins so you can test.
- Press Windows + R, type winword /safe, and press Enter.
- In Word, go to File, then Options, then Add-ins.
- At the bottom, set Manage to COM Add-ins and click Go.
- Uncheck every non-Microsoft add-in, click OK, then reopen Word normally.
If the CPU behaves after that, turn the add-ins back on one at a time until the problem returns. The last one you enabled is the culprit, and you can leave it off.
5. Pause OneDrive and check scheduled tasks
OneDrive and the Office updater share background resources. If OneDrive gets stuck syncing, it can drag the whole system down and make Click-to-Run look worse than it is. Right-click the OneDrive cloud icon in the taskbar, open the settings menu, and choose Pause syncing for a couple of hours. Then watch whether the CPU eases off.
If the spikes come at regular intervals, a failing scheduled task is likely behind them. Press Windows + R, type taskschd.msc, and press Enter to open Task Scheduler. In the library, look for tasks with Office or ClickToRun in the name. If one shows a Last Run Result of Failed over and over, disable it briefly to test whether the CPU settles. Turn it back on afterward if you rely on automatic updates, and again, check with IT first on a work device.
6. Repair Office
A damaged Office install can trap the service in a repair loop. Microsoft’s built-in repair fixes the corrupted files that cause it. Close every Office app first, then follow Microsoft’s steps to repair an Office application.
You get two choices. Quick Repair scans for corrupted files and replaces them, works offline, and takes only a few minutes, so start there. If the CPU is still high afterward, run Online Repair, which does a deeper, full reinstall-style fix and needs an internet connection. It can take 15 to 60 minutes, and CPU running high during the repair itself is normal, so let it finish without cancelling.
Heads up: On a work laptop, update behavior is often set by your IT team through group policy. A local fix can get undone by that policy, so check with IT before changing update settings on a managed device.
7. Clear the Office cache as a last resort
If nothing above sticks, corrupted cache files may be the problem. This is more hands-on, so save it for last. You stop the service, delete its temporary files, and start it again.
- Press Windows + R, type services.msc, and press Enter.
- Find Microsoft Office ClickToRun Service, right-click it, and choose Stop.
- In File Explorer, go to your Office cache folder and delete the files inside it. The path is %LocalAppData%\Microsoft\Office\16.0\OfficeFileCache.
- Go back to Services, right-click the service, and choose Start.
The folder number may differ slightly depending on your Office version. If deleting the cache and reinstalling from your Microsoft account still does not help, the last option is a clean reinstall using Microsoft’s official uninstall support tool, then installing Office fresh from your account.
What about high disk usage?
The same process can show up as high disk usage instead of, or alongside, high CPU. You may even see it hit 100 percent disk right after waking the PC. The causes overlap, so the fixes above apply: it is usually an update staging files, a bloated cache, or a metered flag.
One extra factor matters here. On an older PC with a mechanical hard drive rather than an SSD, disk spikes hurt far more, because the drive simply cannot keep up with the read and write requests. If your machine has an HDD, the process finishing its update work is the real fix, and moving to an SSD is the longer-term cure for that whole class of slowdowns. It is worth knowing this process can appear even on a PC where you think Office is not installed, usually because a trial or a leftover component is still present.
Should you disable Click-to-Run?
For most people, no. Turning it off stops all your security and feature updates, and on Microsoft 365 it can stop Office from opening at all, usually with a “Something went wrong” error. The whole point of fixing the CPU issue is to keep Office working, not to gut it.
The one time disabling makes some sense is on an older, perpetual copy of Office, such as 2019 or 2021, where you are not expecting big feature updates. Even then, setting the service to Manual is safer than Disabled. On Manual, the service stays off while Office is closed and starts itself when you open an app, so you cut the idle CPU without breaking anything.
You cannot uninstall Click-to-Run on its own, either. It is built into Office, so removing it means removing your whole Office installation. If you want to remove Office fully, use Microsoft’s Support and Recovery Assistant, which cleanly uninstalls Office and its Click-to-Run components in one go.
One case is genuinely worth a full removal: a preinstalled trial version you never use. If the process keeps waking up on a PC where you do not run Office, an unused Office trial is often the reason. Removing that trial stops the service from starting at all, and it is the cleanest fix when you have no intention of using the suite.
Frequently asked questions
Why does Click-to-Run start again after I end it in Task Manager?
Because it is a core Office service, not a stray program. Windows restarts it automatically whenever you open an Office app or when a scheduled update is due. Ending the task is only a temporary pause, not a fix.
Is it safe to delete OfficeClickToRun.exe?
No. Deleting it breaks your Office installation and stops updates and repairs. If the CPU use bothers you, fix the cause or set the service to Manual instead. Only remove the file if a scan confirms it is malware in the wrong folder.
Why is Click-to-Run high on one network but fine on another?
The network is almost certainly flagged as metered. Windows does this on hotspots and some Wi-Fi to save data, which makes Office retry updates and burn CPU. Turn off the metered setting for that connection and it usually stops at once.
How long should Click-to-Run stay at high CPU?
A genuine update should calm down within 30 to 60 minutes. Anything longer points to a stuck loop, a metered flag, or a bad add-in. At that point, stop waiting and work through the fixes above.
Will disabling Click-to-Run speed up my PC?
Only while Office is closed, and it costs you all updates. Setting the service to Manual is the better trade: it stays idle when you are not using Office but still starts when you need it, without leaving your apps unpatched.
Conclusion
When Click-to-Run runs high CPU, match the symptom to the cause before changing anything. A short spike is just an update, so wait it out. Steady high CPU usually means a stuck update, a metered network flag, or a broken add-in, so update manually, turn off the metered setting, and test in safe mode. If it holds, run Quick Repair then Online Repair. A good result is the process idling below 5 percent with Office still updating normally.
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