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"The Windows Installer Service could not be accessed. This can occur if the Windows Installer is not correctly installed. Contact your support personnel for assistance."

David Dougherty 0 Reputation points
2025-07-09T01:48:34.61+00:00

Hi, so I've been able to download various programs from the internet, but when I try to download this one program,(a paper day trading program) I'm meet with this message that reads;

"The Windows Installer Service could not be accessed. This can occur if the Windows Installer is not correctly installed. Contact your support personnel for assistance."

I've followed some steps/promts I've come across on YouTube. Where I actually access the Windows Installer which all that did was change the "Startup Type" from Manual(which it was originally) to Active(to which it is now)...but the problem still exists... I've disabled all the anti-virus/firewall protections while attempted to download this software, yet that error message("The Windows Installer Service could not be accessed. This can occur if the Windows Installer is not correctly installed. Contact your support personnel for assistance.") still pops up - not allowing me to download the software.

I've also reached out to the company tech-support team, and they've pretty much just told me everything I've already tried.

I'm just lost as what to do. I'm able to download everything and everything, yet not this one specific software...

Just curious if anyone knows of any work arounds...

I'm running Windows 11 and have WAY MORE than enough space available to download the program. If that info helps out at all...

Thanks!

-David

Windows for home | Windows 11 | Install and upgrade
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  1. Chen1018 13,870 Reputation points Independent Advisor
    2025-07-09T03:41:43.5266667+00:00

    Hi David,

    I'm Cherrelyn. I'm here to help and I know how frustrating this kind of installation error can be.

    Please try these suggestion:

    1. Restart the Windows Installer Service manually

    Press Windows + R, type services.msc, and hit Enter.

    Find Windows Installer, right-click it, and choose Restart (or Start if it’s stopped).

    • Set Startup type to Manual - Active isn't a valid setting and might have caused issues.
    1. Run the installer as Administrator Right-click the program’s .msi or .exe file and choose Run as administrator and this can bypass permission-related blocks.
    2. Re-register the Windows Installer service
      • Open Command Prompt as Admin
      • Run these one by one: msiexec /unregister msiexec /regserver
    3. Check if the program is 32-bit or 64-bit Make sure you’re not trying to install a 32-bit app with a corrupted installer on a 64-bit system and try re-downloading a fresh copy from the source.

    Let me know about my suggestion and I'm here to guide you for further assistance.

    Warm regards,

    Cherrelyn

    1 person found this answer helpful.
  2. Chen1018 13,870 Reputation points Independent Advisor
    2025-07-12T02:22:06.49+00:00

    Hi David,

    Thanks again for the update and screenshots and you're doing everything right, and I really appreciate your patience. Please try to open Command Prompt as Admin, then run these one at a time:

    sfc /scannow

    DISM /Online /Cleanup-Image /RestoreHealth

    These will scan and repair system files. After that, restart your PC and try running the installer again as admin.

    If the issue still happens, let me know and I’ll guide you further. You're getting close!

    Warm regards,

    Cherrelyn

  3. Chen1018 13,870 Reputation points Independent Advisor
    2025-07-11T00:45:52.6+00:00

    Hi David,

    You're doing great, and I appreciate your patience and no worries at all! Yes, the issue was likely just a small formatting hiccup. The correct commands should be typed exactly as below, one at a time, with no extra spaces:

    msiexec /unregister

    Press Enter, wait for the confirmation or just a quick flash (that’s normal), then type the second command:

    msiexec /regserver

    Press Enter again, then restart your PC.

    Once rebooted, try installing your .msi app by right-clicking the installer and choosing Run as administrator.

    Let me know what happens after that and I’m right here to walk with you through the next step if needed!

    Warm regards, Cherrelyn

  4. David Dougherty 0 Reputation points
    2025-07-10T04:04:46.9966667+00:00

    error I was able to use the Terminal Admin option...

    I then type in the first of the 3 words...

    The "msiexec" popped up a prompt which I hit "okay" or something like that, I wasn't able to grab a screen shot.

    But, the second word, " unregister msiexec" typed in gave this error message. Which I thought may have been as a result of using a space inbetween the two words... but that cleary wasn't the case...

    sooo...Am I tying in the words wrong?

    anyway, truly appreciate taking you time to hold me hand through all of this!

    -David

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  5. Chen1018 13,870 Reputation points Independent Advisor
    2025-07-09T07:17:38.53+00:00

    Hi David,

    Thanks for the update and let's take it one step at a time, no worries.

    Please try these suggestion Instead:

    1. Start from Command Prompt as Admin
      • Press Windows + X, select Terminal (Admin) or Command Prompt (Admin)
      • Then type the following, one at a time: msiexec /unregister msiexec /regserver
      • This re-registers the Installer service and often resolves weird behavior.
    2. Restart your PC after that, then try installing your app again by right-clicking it and choosing Run as administrator.

    Let me know how it goes and I’ll guide you through the next step if needed.

    Warm regards,

    Cherrelyn

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