The taskhost.exe application consumes 50-60% of the average cpu usage

I've had a similar issue on an i5 Processor with 8GB of RAM and Windows 7 Home Premium 64-bit. I was cleaning the PC after been infected with some viruses. At the end, all the AV tools that I used, such as ComboFix, Malwarebytes, RogueKiller, Kaspersky IS and so on were showing the PC is clean. But when I open Internet Explorer, it would freeze and not responding. When you reboot, it would hang saying taskhost.exe is closing but it takes forever.

After some digging, because cleaning the RAC database did not help in my case, here is my fix:

1. I opened up Internet Explorer and of course it froze again. I tried resetting it but did not help. I noticed cleaning the History was taking forever and would never finish. So with the IE frozen, I opened Task Manager as well as Resource Monitor
2. iexplorer.exe was red in the Resource Monitor. Right-clicked it and Analyze White Chain - it showed that IE is waiting on taskhost.exe
3. Noticed in Resource Monitor, under Disk activity that taskhost.exe was having a high disk usage and trying to process:

C:\Users<username>\AppData\Local\Microsoft\Windows\WebCache\WebCacheV01.dat

4. To browse that folder and see what is that file, I had to go to Folder Options | View | and un-hide Protected operating system files.
5. I found the  WebCacheV01.dat  file and saw it was huge - over 5GB. In task manager, I killed taskhost.exe, deleted the file and rebooted the PC. Now IE opens lightning fast and I was able to finally run CCLeaner to clean up temp files and so on.

Hope this helps

I am seeing this issue regularly on my Core i5 laptop where 1 core is pegged at 25% CPU.

Using Process Explorer I open up the offending TaskHost to find that one thread is eating 25% of the CPU:

RacEngn.dll!RacSysprepSpecialize+0x428f4

Opening up this thread's stack shows that the thread appears to be stuck here:

ntoskrnl.exe!SeAccessCheckWithHint+0xb4a

ntoskrnl.exe!KeAcquireSpinLockAtDpcLevel+0x7d2

ntoskrnl.exe!KeWaitForMutexObject+0x19f

ntoskrnl.exe!PsIsSystemProcess+0x94

ntoskrnl.exe!KeStackAttachProcess+0x11c1

ntoskrnl.exe!ObReferenceObjectByPointerWithTag+0x233

RacEngn.dll+0x12230

RacEngn.dll+0x1217d

RacEngn.dll+0x120dd

RacEngn.dll+0x19052

RacEngn.dll+0x19e1b

RacEngn.dll+0x191da

RacEngn.dll+0x1cafb

RacEngn.dll+0x118bc

RacEngn.dll+0x117d3

RacEngn.dll!RacSysprepSpecialize+0x42a52

kernel32.dll!BaseThreadInitThunk+0xd

ntdll.dll!RtlUserThreadStart+0x21

Is anyone looking into this because it's causing a major perf and battery-life issue on my (and others') machines?

[Update: 2/2/2011 @ 12:20 PST]

I've posted a more detailed diagnosis of this issue on my blog where I'll also crosspost any answers to this issue.

http://www.bitcrazed.com/post/2011/02/02/Windows’-(RACENGN)-Reliability-Analysis-Calculation-Engine-eating-my-laptop!.aspx

Rich Turner

let's try, to cool down my chipset

beside being here:C:\Windows\System32\Taskhost.exe.

I find this taskhost in : WinSxS\x86_microsoft-windows-taskhost, both as exe and MUI

and cannot delete them,

Thank you, Rich Turner.

I hit this same issue on a friend's laptop--cleaned out the RAC stuff and it's happy now.

There's one difference between the case I noticed and what others are reporting on here, though--in my case it was almost exactly 25% of the CPU power, split across all 4 cores.

In other words, whatever it is that goes wrong it saturates one core, the load being distributed by the task scheduler rather than showing up all on one core.  The people reporting 50% almost certainly have only two cores.

BTW, your links are dead.

http://www.eightforums.com/performance-maintenance/44709-windows-host-process-rundll32-high-cpu-usage.html

OS: Window 8.1, but likely applies to v8 and v10, probably 7 too.

Software: Office 2013 or 2016

Symptom: “Host Process for Windows Tasks” using high CPU, fan spinning, draining battery

Root Cause: Participating in Windows and/or Office Experince program(s) creates a scheduled task that doesn’t terminate itsel.

1. Disable the Customer Experince Improvement Program (CEIP) in Windows
   1. WIN7-81: Search from start menu or navigate to Control Panel\All Control Panel Items\Action Center\Change Action Center settings
2. Disable CEIP in office::
   1. Any office app/File (backstage)/Options?TrustCenter/Privacy Options/Uncheck the “Send personal info to MS….”
3. Change termination of App Experience Program Data Updater
   1. On windows 8.1 go to Charms -> Search. Enter "Schedule tasks"
   2. In the Task Scheduler window in the left hand pane expand "Task Scheduler Library" and go to Microsoft > Windows > Application Experience
   3. There should be 4 entries. The offender that causes the high CPU usage is "ProgramDataUpdater". You could disable it as some have recommended, however I opted to configure the task to kill it self if it runs for more than 1 minute:
      1. Right click on "ProgramDataUpdater" and go to properties
      2. Go to the Settings tab. Ensure that the box next to "Stop the task if it runs longer than." is ticked (checked).
      3. In the drop down selection box, simply type in "1 minute" (or other time limit). Then click OK.
   4. Reboot.