Windows Home Server: Demigrator.exe Interrupts Media Streaming

Up until quite recently I had Windows Home Server (WHS) installed as a virtual machine on VMware vSphere. My Media Center PC was connected to WHS and I would stream High Definition (HD) content between the two without any issues.

The strange thing is, now that WHS is installed on physical hardware, my HD streams are regularly interrupted by Demigrator.exe on WHS – which is very annoying. This could be due to the fact that my media is duplicated on WHS now that it is not virtualized?

I attempted to fix this last night by installing ThreadMaster on WHS and saw some improvements. In about an hour and a half I only noticed two interruptions to a HD steam with ThreadMaster running on WHS – and only one of those interruptions was bad. Previously I might get 3 or 4 interruptions per hour.

ThreadMaster does not have a GUI and must be manually installed and configured. I will include my initial settings as follows, but I will most likely play around with them to see if I can improve things further:

First download ThreadMaster to your WHS and extract it.

Click Start, then Run and type cmd and then click OK. Browse to the location of the extracted files using the cd command, for example:

cd c:\Documents and Settings\Administrator\Desktop\tminst112

Then type install.bat into the command prompt and then press Enter. This will install ThreadMaster.

ThreadMaster is configured through the registry, so click Start and then Run again and type regedit and then click OK. Browse to HKEY_Local_Machine\SYSTEM\CurrentControlSet\Services\ThreadMaster\Parameters. As you can see there are two Parameters that I have set.

  • CPUThresholdPct is the CPU load threshold per application. This is a global setting and affects all applications, unless specified in the “Application” or “Exceptions” sections. Default: 15%, Valid range 3 – 100.
  • MainSampleTime is the time period used for calculating the average CPU utilization for applications. Default: 30 seconds. Values above 10 seconds accepted.

In the Applications section you can see that I have added Demigrator.exe and given it the value of 5. Here 5 represents the CPUThresholdPct for Demigrator.exe.

I will play with these settings over time, and hopefully be able to view media without interruption, but for now these settings have helped fairly well.


Since creating this post I have been regularly been adding HD content to my WHS courtesy of a newly acquired HD Homerun (recording .wtv streams from Comcast). All of this content lands in the Recorded TV folder which is set for duplication – sadly I have still been noticing demigrator.exe interrupting my WHS media streams.

My revised solution for now is simply to schedule when demigrator.exe can run, as per the following scripts by GaPony on the We Got Served forums:


@echo off
sc stop "DriveExtenderMigrator"
sc config  "DriveExtenderMigrator" start=  disabled


@echo off
sc config  "DriveExtenderMigrator" start= demand
sc start "DriveExtenderMigrator"

I scheduled these batch files using Task Scheduler on WHS (Start, All Programs, Accessories, System Tools, Task Scheduler).

11 thoughts on “Windows Home Server: Demigrator.exe Interrupts Media Streaming

  1. I used to have similar issues with my WHS machine, and to my experience this was caused by two factors:
    1) TwonkyMedia which was constantly scanning my data (thanks to a bug that for some reason HP doesn’t care about fixing by updating to the latest version). This is not necessarily related to demigrator.exe, but it played its role in hogging the CPU; and
    2) Those ‘New Format’ hard disks that are incompatible with Windows XP and 2000 operating systems. Yes, you’ve heard of them, those WD Green 1.5/2TB hard disks. Google them if you haven’t. This gave me very bad performance while the demigrator.exe was balancing my data across the disks: read/write speeds between 1 and 3 MB/s, which is clearly not enough to stream HD content. Moving all of my data onto a USB hard drive temporarily, and setting the correct jumper on both my WD disks has completely solved my problems. (FYI, the OS itself is installed on another, smaller disk.)

    Nevertheless, I wish you good luck in tweaking demigrator. It was an interesting read.

    1. Thanks for you comment Maxine, you are quite right that incorrectly set up Advanced format drives can be very very slow! You also reminded me of one other tweak that I performed on WHS, and that was to disable the Windows Search service (as this will sometimes kick in and severely interrupt media steaming).

      You can also see on other blog posts the issues that I have had with Advanced format drives:

      Interesting Microsoft does not officially support Advanced format drives on WHS:

      1. Hi Mike,

        Quick question.. I noticed in your capture that you have placed “demigratror.exe” and not “demigrator.exe” – I assume you have corrected it on your end or this entire setup would not effect the demigrator.exe it self…


  2. Demigrator is a pain.

    My solution was to set it as disabled by default, then enable and start at 4am using scheduled tasks when not even I am watching. Set two more tasks to disable then stop at 6am and all set.

    Not ideal, but it also allows the disks to spin down for much longer periods of time.

    6MB/sec HD streams and demigrator do not play well with 5400rpm drives that can be as low at 50MB/sec on the end tracks.

    1. That’s an interesting solution Gary – I think that this might have to be the next step. I would have hoped (given the issues with Demigrator.exe) that Microsoft would have included some kind of scheduling option via a PowerPack but alas they have not!

  3. I had the same problem and the only solution I found was much the same as Gary’s.

    My WHS sleeps between midnight and 5am so the demigrator service is stopped and disabled at 7am and started again at 11pm.

    It gives it time to balance my data but only when I’m not going to be watching TV from my WHS.

    Incidently, it causes problems with SD TV as well as HD TV.

  4. I thought demigrator was causing issues on my WHS setup. I could generally watched ripped dvd’s fine, but a ripped bluray would skip and stutter. I did the above suggestion of having tasks stop and start demigrator so it only ran in the wee small hours.

    That helped for a while, then it got bad again. Turned out that a hard drive was failing. By the time I copied the files off and removed the drive the 2TB was now containing over 900MB of bad sectors. I didn’t lose a single file though (thanks to WHS and the wonderful duplication feature).

    When copying to/from the WHS machine, it was only at about 23MB/s. Now if I see that again I will know the problem and replace a drive sooner.

  5. I have updated this post and have scheduled two batch files to turn demigrator.exe on and off – this should give me uninterrupted media streams while demigrator,exe is off. It is quite disappointing that Microsoft has not fixed this issue yet!

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s