The system that I'm looking at is Windows 7, 32bit.

When the system boots up it spends a ton of time reading and writing to the DataStore.edb file which is located in Windows\SoftwareDistribution\DataStore directory. This makes the system run really slow for several minutes, probably about 10 if I'm honest. If you stop the Windows Update service, within a minute the system will stop reading and writing from the file and everything runs smoothly.

Things I've tried:

I've stopped Windows Update, deleted the file, rebooted, but when I do that Windows rebuilds the file until it's a few hundred MB in size. Once Windows is happy with whatever it's doing, it stops and my disk usage and cue drop down to normal levels and the system does whatever you want with plenty of speed.

I've booted into SafeMode and run several virus scans and Kaspersky's RootKit killer tool and nobody finds anything offensive.

What should I try next?


9 Answers 9


I know it's way past the point of being able to provide a suitable solution for you now, but I have exactly the same thing with a Windows 7 machine at work. For future reference, you can always check the integrity of (/g) and/or defrag (/d) *.edb files with esentutl.exe.

e.g. esentutl.exe /d c:\Windows\SoftwareDistribution\DataStore\DataStore.edb

If you are unable to run this command with "-1032" error, you can boot into safemode (without networking) and run the command from there. You might first need to run it with the /p switch to repair file corruption.

  • I tried this and I received the following message: Error: Access to source database 'c:\Windows\SoftwareDistribution\DataStore\Data Store.edb' failed with Jet error -1032.
    – Alf47
    Jun 10, 2015 at 14:20
  • 4
    @Alf47 Stop the Windows Update service and try again
    – Drakarah
    Jul 10, 2015 at 13:14
  • 3
    @Alf47 You need to run Command Prompt as administrator to have access. Sep 2, 2015 at 8:33
  • And it is "c:\Windows\SoftwareDistribution\DataStore\DataStore.edb". No space!
    – rdtsc
    Jul 4, 2017 at 15:31

RAMMap showed that C:\Windows\SoftwareDistribution\DataStore\DataStore.edb mapped file was wasting 400 Mb of my precious RAM. Moreover Windows Update was constantly slowing down the system in process of updating that huge file.

esentutl.exe just reduced DataStore.edb size from slightly more than 600 Mb to slightly less that 600 MB and proved to be useless in my case.

http://juneyourtech.blogspot.com/2013/06/datastoreedb-and-windows-vista.html states that deleting this file is also not an option as Windows Update would rebuild it to the same size of next run.

So I had to completely disable Windows Update Service autorun. This greatly lowered waste of RAM, CPU and disk IO. The system is much more responsive now.

See also How to schedule download of windows 7 updates? for a way to launch update using Windows Task Scheduler.


Take a look also at Windows 7 SP1 Windows Update stuck checking for updates

  • BTW, after free update to Windows 10 on the same old hardware the problem didn't reproduce.
    – Vadzim
    Sep 15, 2017 at 8:59

Expanding upon @mafbailey 's answer (And a big thanks to you, as well!) make sure to open the command prompt as an administrator when utilizing the following command line action to have the appropriate file permissions.

I'd have been stuck had I not known =)

esentutl.exe /d c:\Windows\SoftwareDistribution\DataStore\DataStore.edb
  • Also stop Windwos update services from 900Mb => 898MB
    – user956584
    Oct 21, 2015 at 19:40
  • An inferior copy of an existing answer. Aug 28, 2017 at 7:42

I have experienced the same problem with a slowly starting computer running w7 home edition. Opening email or firefox was frustrating.

On my computer, during start up, the anti virus program (windows essentials) seemed to be taking a lot of time on the datastore.edb file.

This link about "Improve PC Performance and Stability by Properly Configuring Anti-Virus" solved the slow start up problem for me.

The solution basically involves telling the virus scanner (windows essentials) to exclude checking this file. I did the other exclusions on the windows files as well. (but i'm fine with the scanners checking my photos, even though they should be safe)


Try installing Windows Update KB3050265, released 2nd June 2015.

This is optional so you may have to look for it in Control Panel > System and Security > Windows Update > Show all available updates > Optional, and manually install it.

  • 1
    This didn't help, I already have that update and still wake-up from hibernation is slow, and restart even much slower.
    – Danijel
    Jul 2, 2015 at 7:27

Fixing Windows Update, this method is for Windows 7

Go to Programs \ Accessories: Cmd prompt

Click the right mouse button and run as administrator.

In the prompt window follow the sequence below:

net stop wuauserv (after Enter)

net stop bits (after Enter)

In Windows Explorer:

Go to the folder windows\software distribution\download (delete everything in there)

Go to the folder windows\software distribution\DataStore (delete everything in there)

Go to the folder windows\software distribution\DataStore\Logs (delete everything in there)

Go to the folder windows\software distribution\PostRebootEventCache (delete everything in there)

The CMD prompt window:

net start wuauserv (after Enter)

net start bits (after Enter)

Sources:- http://tecnicoinformaticacuritiba.com.br/corrigindo-windows-update/ / https://social.technet.microsoft.com/Forums/pt-BR/d75e92b9-4caf-425d-b841-0bae79f7adf1/windows-7-windows-update-no-funciona?forum=winvistapt


Microsoft released a new WindowsUpdate Client Update to fix the slow Update searching/Installation.

Installing and searching for updates is slow and high CPU usage occurs in Windows 7

32Bit: http://www.microsoft.com/downloads/details.aspx?FamilyId=fcd6bf5d-f004-4ca3-aa7e-1de462b91dd0

64Bit: http://www.microsoft.com/downloads/details.aspx?FamilyId=4fe566bd-31b1-4413-8c4c-412b52533669

This updates reduces the detection time and uses less RAM. So try it out

  • warning: after installing this, Windows Update now does not work at all, it immediately gives error "WindowsUpdate_80244019" "WindowsUpdate_dt000" which I've been unable to solve
    – M.M
    Dec 25, 2015 at 11:21
  • Uninstalling this update did return me to the previous situation I was in
    – M.M
    Dec 25, 2015 at 11:27
  • @M.M error 80244019 means WU_E_PT_HTTP_STATUS_NOT_FOUND Same as HTTP status 404 - the server cannot find the requested URI (Uniform Resource Identifier). which av suite/firewall do you use? Dec 25, 2015 at 15:51
  • MS Security Essentials, and no firewall . Rest of internet was working fine (including IE)
    – M.M
    Dec 25, 2015 at 20:38
  • @M.M try at least the June 2015 version which first includes the memory usage fix: support.microsoft.com/en-us/kb/3050265 Dec 26, 2015 at 9:44

I don't know why this says that I posted this in January 2013, this problem was only a few months ago in 2015. Ha!

Anyway - I'm sorry to waste everyone's time. For some reason I wasn't getting notifications about this thread until today, December 9, 2015.

I tried a number of things and ended up on the phone with the manufacturer of the device that this computer was within. It turns out that they have a bug in their implementation of Windows that causes this to happen. The only solution to the problem is to re-image the machine and hope it doesn't happen again.

This applies to Zeiss OCT machines for those who are wondering.


I have run into similar problems.
I installed KB3050265 from the website and it solved all these problems.
Make sure you install the correct version for your Windows ( 64 bit (x64) or 32-bit (x86))

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