Fix Microsoft Compatibility Telemetry High Disk Usage

If Microsoft Compatibility Telemetry (also called CompTel or CompatTelRunner.exe) is causing high disk usage on your Windows PC, the most effective fixes are to disable the scheduled tasks that run it, turn off the “Send diagnostic data” setting, or, in more persistent cases, disable the DiagTrack service. This article explains why this process runs, how to stop it safely, and what to do if it keeps coming back.

What Is Microsoft Compatibility Telemetry?

Microsoft Compatibility Telemetry is a background component of Windows 10 and Windows 11. Its official purpose is to collect diagnostic and usage data about your system and send it to Microsoft. The data helps Microsoft identify compatibility issues with hardware and software, so future updates can avoid breaking things. The process name is CompatTelRunner.exe, and it is typically triggered by a set of scheduled tasks that run at various times, such as after a system update or during idle periods.

While the data collection is benign, the process is known to cause high disk usage, especially on machines with traditional hard drives (HDDs) or older SSDs. Users often see disk usage spike to 100% for minutes at a time, making the system sluggish or unresponsive. This is not a sign of malware; it’s a known performance issue that has been reported since Windows 10’s early days.

Why Does It Cause High Disk Usage?

The telemetry component scans your system for installed software and hardware, then compresses and uploads the data. On a system with many files or a slow disk, this scanning and compression can be resource-intensive. The scheduled tasks are set to run at logon, at idle, and after updates, so you may notice the spike right after booting your PC or after installing a Windows update. The process can also run in the background for several minutes, which on a mechanical drive can saturate the disk’s read/write capacity.

Another contributing factor is that the telemetry service (DiagTrack) is set to start automatically and can re-trigger the scheduled tasks even after you’ve manually killed the process. This is why simply ending the task in Task Manager is not a permanent fix.

How to Disable Microsoft Compatibility Telemetry (Step-by-Step)

There are three main methods to stop the high disk usage. Start with the first, and if the problem persists, move to the next. All methods require administrative privileges.

Method 1: Disable the Scheduled Tasks

1. Press Windows + R, type taskschd.msc, and press Enter.
2. Navigate to Task Scheduler Library > Microsoft > Windows > Application Experience.
3. In the list, find tasks named Microsoft Compatibility Appraiser, ProgramDataUpdater, and StartupAppTask.
4. Right-click each one and select Disable. Do not delete them—disabling is reversible and safer.

This stops the telemetry from running on a schedule. However, some updates may re-enable these tasks, so you might need to redo this after major Windows updates.

Method 2: Turn Off Diagnostic Data in Settings

1. Open Settings > Privacy & Security > Diagnostics & feedback (Windows 11) or Settings > Privacy > Diagnostics & feedback (Windows 10).
2. Set Diagnostic data to Required diagnostic data (Windows 11) or Basic (Windows 10).
3. Turn off Tailored experiences and Improve inking & typing if present.

This reduces the amount of data collected, but it does not completely stop the telemetry process. It’s a good first step, but often not enough to eliminate disk usage.

Method 3: Disable the DiagTrack Service

1. Press Windows + R, type services.msc, and press Enter.
2. Scroll to Connected User Experiences and Telemetry (the service name is DiagTrack).
3. Right-click it, select Properties.
4. Set Startup type to Disabled.
5. Click Stop to stop the service immediately, then click OK.

Disabling the service is the most thorough fix. It prevents the telemetry from running at all. Some Windows updates may re-enable the service, so check it again after major updates.

What If the Problem Persists?

If you’ve disabled the scheduled tasks and the service, but disk usage remains high, the culprit may not be telemetry alone. Other common causes of high disk usage include:

• Windows Search indexer – Rebuilding the index after an update can cause high disk usage. You can temporarily disable search indexing in Services (Windows Search) to test, but this will slow down file searches.
• Superfetch/SysMain – This service preloads apps into memory. On HDDs, it can cause disk churn. You can disable it in Services, but it may reduce app launch speed.
• Antivirus scans – Third-party antivirus or Windows Defender full scans can saturate the disk. Check your antivirus’s scan schedule.
• Windows Update – Downloading and installing updates can cause high disk usage, but this should be temporary.

If you’ve ruled out telemetry, open Task Manager and sort by “Disk” to see which process is actually using the most. If it’s not CompatTelRunner.exe, the issue is elsewhere.

Is It Safe to Disable Telemetry?

Yes, disabling Microsoft Compatibility Telemetry is safe for most users. You will lose the personalized tips and tailored experiences, and Microsoft won’t receive diagnostic data about your system. This does not affect Windows Update, security patches, or the core functionality of Windows. The only downside is that Microsoft won’t be able to fix compatibility issues that are specific to your hardware, but this is rarely noticeable for the average user.

It’s worth noting that some enterprise and education editions of Windows may have group policies that force telemetry on. In those cases, you may need to contact your IT administrator. For home users, the methods above work.

Frequently Asked Questions

Will disabling telemetry break Windows updates?

No. Windows Update is a separate service and will continue to work normally. Disabling telemetry only stops the diagnostic data collection, not the update mechanism.

Why does CompatTelRunner.exe keep coming back after I disable it?

Windows Update can re-enable the scheduled tasks or the DiagTrack service during major feature updates. You may need to reapply the changes after each significant update. Some users also find that the tasks are re-created by the OS if the service is still running, so disabling the service is the more reliable fix.

Is Microsoft Compatibility Telemetry malware?

No. It is a legitimate Windows component. However, because it runs frequently and uses disk resources, some users mistake it for malware. If your antivirus flags it, it’s likely a false positive, but you can verify the file location: it should be in C:\Windows\System32 or C:\Windows\SysWOW64.

Can I delete CompatTelRunner.exe?

It’s not recommended. Deleting system files can cause instability and may trigger System File Checker to restore it. Disabling the tasks and service is the proper way to stop it.

Will disabling telemetry improve my gaming performance?

It can reduce background disk usage, which may help on systems with slow HDDs. On modern SSDs, the impact is minimal. If you’re experiencing stutters due to disk saturation, disabling telemetry might help, but it’s not a guaranteed fix for all performance issues.

What is the difference between CompatTelRunner.exe and DiagTrack?

CompatTelRunner.exe is the executable that performs the telemetry tasks. DiagTrack is the Windows service that manages the data collection and upload. Disabling the service effectively stops the executable from being launched.

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