The Windows Servicing Guy

Tips and tricks from a Windows support engineer on issues related to servicing

Why does CheckSUR take a long time to run?

Why does CheckSUR take a long time to run?

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I've been asked a lot recently about the CheckSUR utility that our engineers send to customers to assist with servicing corruption issues.  I typically ask that all of our engineers run this tool regardless of the "ease" of the potential fix and the utility gives us a lot of information about the state of the serviving stack when issues are present.  Additionally, the tool was built around specific scenarios that we know we can fix, so this can and does resolve a lot of servicing issues just by running it.

The main question we get though is why does it take so long to run?  I've heard any number of reasons but wanted to give the limiting factors when it comes to running the tool.  The main thing is the spindle speed of the disk on the system you are running the tool on.  This is because the CheckSUR utility comes as a packaged payload.  We create the \Windows\CheckSUR directory on your system and then unpackage the contents of the utlity to your local drive before we ever run the actual tool.  This takes up the majority of the time (~75-80%).  The rest of the time is used for running the tool and generating the log file.  If you have a large amount of corruption on the system, such as a failed service pack, then it may take a little longer but in general the tool should be usable in about 15mins from the time the installer starts.

If you need to run the utility again on the system, you should be able to just re-run the utility you've downloaded (assuming you kept it) and it will be much quicker because it doesnt need to rebuild the directories for the \Windows\CheckSUR directory and can just run the tool.  All of the log files for the utility are held in the \Windows\Logs\CBS\CheckSUR.log file.  We will recreate this file each time the utility is run so the only the most current entries will be in the log.

If you were unaware of the utility or would like more information on it, please see the following:


  • I think CheckSUR's description on the Download Center pages is confusing (I think MS just copy-pasted the description from Windows Update where it is appropriate as Windows Update actually scans computers and then offers fixes). The download center description should say "Use this tool to fix a *potential* inconsistency which *may have developed* in the Windows servicing store which may prevent the successful installation of future updates, service packs, and software." It says "an inconsistency *was* found" which confused me when I first read it. Then again, the design of the NT6 servicing stack needs to be changed in the future to entirely eliminate corruption, slowless, taking up so much disk space and have the ability to slipstream back.

  • "We create the \Windows\CheckSUR directory on your system and then unpackage the contents of the utlity to your local drive before we ever run the actual tool.  This takes up the majority of the time (~75-80%)."

    Perhaps it is a good candidate for FirstLogonCommands?

  • Drew,

    Do you mean as an enterprise wide solution?  Just trying to understand why you would want to use FirstLogon?


  • Yes, as an enterprise solution:

    1. To save time (as per this post)

    2. So it is just there if needed (as though it were an inbox tool)

    Hopefully this can be done without issue.

  • Well part of the problem with that solution is that CheckSUR doesnt run as a standalone tool once its installed.  You have to download it each time you want to use it, but the second running of the tool will take less time because the payloads will already be installed on the system.

    Hope that makes sense.

  • Not really!

    Each time i run 'start /wait wusa.exe Windows6.0-KB947821-v11-x86.msu /quiet /norestart' i get three new processes - checksur.exe, checksurlauncher.exe, CheckSURPackage.EXE. CheckSUR.log gets updated after several minutes, and info is appended to CheckSUR.persist.log. No errors reported.

    Also, if i firstly delete C:\Windows\CheckSur\v1.0\*  the extraction time only seems to add around a minute, but the total checksur.exe time is ~10 minutes.

  • "15 mins?"  Who are you kidding??  CheckSUR actually runs for about two HOURS, with no indication of what it is doing, or how long it will take, or whether it is stuck, or even what its actual purpose is.

    This is TERRIBLE human factors engineering -- so typical for Microsoft!  Come on, Microsoft, do you really want millions of people to spend an extra $1000 each to buy Apple computers, just to avoid Microsoft's miserable software quality?  No?  Well, then, WHY does Microsoft abuse its customers like this??

    BTW, I can be reached at:

  • Great, now that means another hour and a half of waiting and misery.

  • CheckSUR rarely has taken more than 15mins and I've run it literally hundreds of times with customers.  I'd be interested to know what your output looks like if its taking 1.5hrs.

  • Its true.. its taking so much time..!! Keep Running and No idea.. What it is doing? (At least there should be some screen Like other installer where we would be knowing where we are?).

    I Passed approx 30mins and till now its running..

  • I'm an hour in and still waiting! Good opportunity to browse for an alternate OS!

  • @James,

    If its taking that long either you have a lot of corruption in servicing (or on your disk) or you have a different type of problem.  I'd be interested to know the outcome unless you've decided to go with another operating system.

  • I'm finding the same ... CheckSUR runs for at least 1.5 hours.

  • I am dealing with a corrupted Vista 64 bit SP2 installation that would NOT upgrade to Windows 7 Ultimate 64 bit. I found CheckSUR and began running it approximately 3 hours ago. CheckSUR has been taking about 4 to 10 percent of my quad-core processor and has been utilizing the hard disk at about 20 Mbps for the entire 3 hours.  I have no idea how much longer it may take. The "Installing" status bar moved to 50 percent within 3 minutes, and has been frozen there for the last 3 hours.

  • While running CheckSUR this evening, I also encountered the long wait with the CheckSUR progress bar not moving for a long period of time.

    Whenever I have processes that appear to be hanging, I fire up good ole Process Explorer from the Sysinternals Suite to see if I can determine what is happening.

    You can find Process Explorer on the Microsoft Technet Site here:

    Upon looking at the CheckSur Log located at C:\Windows\Logs\CBS\CheckSUR.log, it was apparent that CheckSUR was Checking Component Store.

    I started up Process Explorer and found the CheckSUR.exe process and was able to watch as CheckSUR accessed each of the Component Keys in the Windows Registry.

    So, it was obvious that CheckSUR was working, slowly but surely.

    Eventually CheckSUR did complete and added the following to the end of the CheckSUR.log file:


    Seconds executed: 1970

    No errors detected