CompatTelRunner.exe

Windows ProcessMicrosoft Corporation

Also called compattelrunner, compatibility telemetry, microsoft compatibility telemetry

WindowsSystem Component

Compatibility Telemetry runner. Scheduled tasks start it to collect compatibility data Microsoft uses for upgrades and problem reports.

What you need to know

This is Compatibility Telemetry, a scheduled Microsoft task. It is not Defender and it is not a browser.

CompatTelRunner.exe runs Microsoft Compatibility Telemetry. High disk for a while after an upgrade is common. Disabling the scheduled task is the supported control, not deleting System32.

Safe?: Yes, in System32
High disk?: A compat scan can do that
Can I disable it?: Through the task, not by deleting the file

Feex says

If CompatTelRunner is the disk hog after a feature update, I would let the task finish once. I would not rename the exe. That is how servicing repairs start failing.

What is CompatTelRunner.exe?

CompatTelRunner.exe is the host for Microsoft Compatibility Telemetry. Task Scheduler launches it from Microsoft / Windows / Application Experience.

What does it do?

It inventories apps and drivers that might break on a newer Windows. It is not CompatTelRunner collecting passwords. It is not SearchIndexer.exe.

Why is it running?

A daily or idle trigger fired, or you just installed a feature update. A runner that never exits for days is stuck and worth a task restart.

Is it safe?

Usually safe

System32 CompatTelRunner is Microsoft. The same filename in a "disable telemetry" zip is not.

A legitimate copy normally runs from:

C:\Windows\System32\CompatTelRunner.exe

Started by Application Experience tasks
Not Windows Search
Not Defender

Can I end it?

Stops this run

Ending CompatTelRunner.exe stops the current inventory. The task will start again on the next trigger unless you disable that task.

Can I remove it?

Do not delete CompatTelRunner.exe. Disable Microsoft Compatibility Appraiser in Task Scheduler if you accept less upgrade-readiness data.

Should it start with Windows?

A scheduled task starts it. It should not be a Startup Apps row.

Normal resource behavior

These are contextual labels, not universal averages.

CPU: Can rise while inventorying
Disk: The usual complaint on HDD
Network: If diagnostic sending is allowed
Memory: Moderate

File information

CompatTelRunner.exe file information
Executable name	CompatTelRunner.exe
Common legitimate path	C:\Windows\System32\CompatTelRunner.exe
Publisher	Microsoft Corporation
Signature expectation	Signed by Microsoft Windows

Common problems

100 percent disk for an hour

On a spinning disk the Appraiser is slow. Wait, then check Task Scheduler history. SearchIndexer is a different row if the disk stays busy.

Scripts that take ownership of the file

Those break servicing. Use the task, not ACLs.

Troubleshooting

Diagnose before you change anything destructive.

Task Scheduler > Application Experience

Microsoft Compatibility Appraiser is the usual name.

Do not replace the runner

Windows Update will fight you.

Technical details

CompatTelRunner.exe technical details
Image name	CompatTelRunner.exe
Role	Compatibility Telemetry runner

Sources and verification

Reviewed by Feex editorial. Last verified August 2026 Status: Feex Reviewed. How we research.

Microsoft Support: Compatibility Telemetry · Diagnostic tasks
Microsoft Learn: Task Scheduler · Microsoft Compatibility Appraiser task
Foxhole process map · First-party samples on Windows PCs. Not a lab benchmark.

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