Question: I have a fast computer (quad-core i7, 3.5 Ghz, 24 GB of RAM, Windows 8.1) and I installed a new hard drive less than a year ago that was supposed to be as fast as you could buy for an HHD and not an SSD.

On boot, the computer is extremely slow for about 20 minutes (literally 20 minutes). Nothing will load. Opening programs will just hang.

Went into Resource Monitor and found that my disk I/O is at 100% that entire period. In fact, it looks like one program is just going to town on my disk: CompatTelRunner.exe. I’ve Googled it, but there are hardly any results, so I don’t know what service this is.

Here are some screen shots at 5 and 10 minutes in:

It could be a hard drive issue (Windows 8.1 Update 1 Disk Usage 100%), but HD Tune shows burst rate at 22.8 MB/s and average around 81.0 MB/s

Answer: You can disable the scheduled tasks that starts CompatTelTunner.exe by looking in the Task Scheduler.Computer Management �C System Tools �C Task Schedule Library �C Microsoft �C Windows �C Application ExperienceorStart – Run – taskschd.mscName: Microsoft Compatibility AppraiserLocation: MicrosoftWindowsApplication ExperienceCollects program telemetry information if opted-in to the Microsoft Customer Experience Improvement Program.Right click on Microsoft Compatibility Appraiser and select Disable By default, it is set to start if there is ANY network connection.

The executable is located here:C:WindowsSystem32CompatTelRunner.exe ?

You may also want to look at the following:Customer Experience Improvement Program states

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If the user has consented to participate in the Windows ?Customer Experience Improvement Program, this job collects and sends ?usage data to Microsoft. However, it is set to run even if opted out ?Siuf (under Feedback)