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Fix CNMSSC DLL Error In Windows 11

July 7, 2022

Some Windows users report that every time they start their computer they get an error pointing to a problem with CNMSSC.DLL what does it say Not a valid Win 32 application. This problem is much more prevalent in older versions of Windows (Windows 7, Windows 8.1, and Windows 10), but there are also reports of it occurring in Windows 11. Here, we’re going to help you fix the problem. CNMSSC DLL error.

Index of contents

  1. What Causes CNMSSC DLL Error?
    1. Disable the Canon printer process (if applicable)
    2. Uninstall the Canon printer software (if applicable)
    3. Clean shell home folder
    4. Remove responsible startup item via Autoruns
    5. Update Windows to the latest version
    6. Remove cnmssc~1.dll from Registry Editor
    7. Implement a clean boot
    8. Start a security scanner scan
    9. Run a Malwarebytes scan
    10. Perform a repair or clean install

What Causes CNMSSC DLL Error?

After investigating this particular issue, it turns out that there are several scenarios that could end up causing this error. Here is a list of possible culprits that you should be aware of if you are currently experiencing this issue:

  • Conflicting Canon Process: It turns out that this particular problem is often caused by a process in the Canon printer. There is no official explanation as to why this is happening, but community members are reporting that it is probably due to a conflicting driver interfering with the CNMSSC.DLL file. To fix the problem if this scenario is applicable, you should try to forcefully stop the Canon Printer process via Task Manager or simply uninstall the main software (Canon Printer Software) in case the first method is not successful. cash.
  • Corrupt startup key: If you are receiving this error every time your computer starts up, it is very likely that you are experiencing this behavior due to a rogue startup item calling CNMSSC.DLL even if the file is no longer present on your printer. You can correct this behavior by cleaning the Shell startup folder or by running the Autoruns software to remove any unauthorized startup items.
  • Outdated version of Windows: It turns out that this problem could also be related to your current version of Windows. Several users facing the same type of issue have confirmed that once they updated their version of Windows to the latest version, the issue related to CNMSSC.DLL stopped occurring.
  • Remnant key cnmssc~1.dll– Depending on how you uninstalled the Canon printer software and associated dependency, you may end up experiencing this error on every startup due to a registry key that is still calling the now missing file even though it is no longer present on your system . In this case, the only way to resolve the problem is to remove all mentions of cnmssc~1.dll from your Registry cluster via Registry Editor.
  • Interference from third-party applications– It turns out that this problem can also occur due to some kind of interference caused by some printer support applications or security suites that are blocking the DLL from taking action. You can test this theory by implementing a clean boot and see if the error stops occurring. If the error no longer occurs while in clean boot mode, you can systematically get rid of all third-party suites until you identify the culprit.
  • Security problemNote: Under certain circumstances, you can expect to deal with this issue after your antivirus package ended up quarantining the CNMSSC.DLL or an associated dependency. In this case, our recommendation is to run a deep Microsoft Safety Scanner scan and supplement it with Malwarebytes to make sure your PC is no longer infected. A Malwarebytes will also clean any startup items that may be causing this error.
  • Damage to system files: Depending on the origin of this problem, this error can also be caused by some kind of system file corruption that is currently affecting your system. In this case, the fastest and most efficient way to resolve the issue is to implement a clean install or repair install procedure.

Now that we have reviewed all the possible causes that could trigger the CNMSSC DLL error, let us go through all the confirmed solutions that other affected users have successfully used to get to the bottom of this problem.

Disable the Canon printer process (if applicable)

If you are just starting to troubleshoot this particular issue, the first thing you should do is check if the issue is often caused by the Canon printer process.

There is no clear explanation why this happens (from Microsoft), but it may be due to a Canon driver conflict interfering with the CNMSSC.DLL file.

If this scenario is applicable, the easiest way to fix the problem is to try force stopping the Canon Printer service via Task Manager.

Several affected users have confirmed that they stopped seeing the CNMSSC.DLL-related error after using Task Manager to effectively disable all Canon-related printer services.

Follow the instructions below for specific instructions on how to do this:

  • press Ctrl+Shift+Enterto open the Task Manager in you
  • If the simple interface is open by default, click Show more details to open the expert interface of Task Manager.

  • Once you’re inside the expert interface in Task Manager, access the Startup tab, then go ahead and find each Canon printer process and disable it (by right-clicking on it and clicking Disable in the menu contextual).

  • After all Canon startup services have been disabled, restart your PC and see if the error stops occurring.

If the same error still occurs of CNMSSC.DLL, please try the following method below to uninstall the potentially conflicting Canon printer software.

Uninstall the Canon printer software (if applicable)

If the first method didn’t work for you, the problem is probably caused by the main startup service application (which we tried to disable in the previous method).

If this scenario is applicable, the next logical step would be to uninstall the main application: Canon Printer Software.

Note: only consider this method if you are not actively using the canon printer software or any associated dependencies or features. If you use the native printing feature in Windows, you can easily uninstall the software as the native printing protocol will be used instead.

In case this method is suitable, follow the instructions below to uninstall the Canon printer software:

  • press Windows key + R to open a dialog Run.
  • Then write ‘appwiz.cpl’ inside the text box and press Ctrl+Shift+Enter to open the menu Programs and characteristics with administrator access.

  • If he User Account Control (UAC) requests it, click on Yes to grant administrator access.
  • Once you are inside the menu Programs and characteristicsscroll down through the list of installed programs and locate Canon printer software.
  • When you see it, right click on it and select uninstall in the context menu that just appeared.

  • Inside the uninstall screen, follow the detailed steps to complete the uninstall, then reboot your PC and see if the problem is fixed once the next startup completes.

If the issue is still not resolved, please scroll down to the next potential solution below.

Clean shell home folder

If you see this error every time your computer starts, it’s probably because a rogue startup item is calling CNMSSC.DLL, even if the file is no longer on your printer. You can fix this by cleaning the shell startup folder or by running Autoruns to remove any unauthorized startup items.

This method was successfully used by many Windows 10 and Windows 11 users.

Note: all you need to do is open the shell startup folder and delete all unsolicited startup items from there.

For step-by-step instructions on how to do this, follow the next step:

  • press Windows key + R to open a dialog Run.
  • Then write ‘shell: startup’ inside the text box, then press Ctrl+Shift+Enter to open the folder Shell Startup with admin access.
  • If requested by the User Account Control (UAC), click on Yes to grant administrator access.
  • Once you are inside the folder Startpress Ctrl + A to select everything inside, then right-click a selected item and click Remove in the context menu that just appeared.

  • After deleting all startup items from the Startup folder, repeat the action that was causing the CNMSSC.DLL and see if the problem is now fixed.

If the issue is still not resolved, move on to the next method below.

Remove responsible startup item via Autoruns

If you’re getting startup errors related to the CNMSSC.DLL file, it’s likely that your security suite removed a malicious file that was part of the infection.

It is not uncommon for some security suites to lose some files when it comes to infections. Sometimes startup items and registry keys will remain on the system, calling the malicious file to run even if the file was removed by the security suite. Whenever this happens, Windows will automatically trigger an error popup.

There are several ways to deal with an error associated with the dnsapi.dll file, but let’s find the easiest approach of the bunch.

Note: Autoruns is Microsoft-vetted software that can identify, organize, and remove runonce, run, startup folders, and unused registry keys.

In our case, we can use it to identify and remove the startup items (or registry keys) that are calling the file that is no longer there. Here is a quick guide to installing and using Autoruns to remove errors associated with the CNMSSC.DLL file:

  • First, let’s download the latest version of the Autoruns utility.
  • To do this, visit the Autoruns download page from any browser to start the download.
  • Once you are inside the correct page, click Download Autoruns and Autorunsc.

  • After the download is complete, extract the .zip file and double click on the executable Autoruns to open it.
  • After Autoruns opens, wait until the All listthen scroll down through the list of available Autorun entries and locate CNMSSC.DLL (see image path).
  • Once you see it, right-click on it and select Delete from the context menu to prevent the executable from being called at system startup.

  • Reboot your computer and see if you see any CNMSSC.DLL prompts at system startup.

If the issue is still not fixed, move on to the next method below.

Update Windows to the latest version

It turns out that this problem could be related to your current version of Windows. Several users who experienced the same issue have confirmed that upgrading their version of Windows to the latest version stopped their CNMSSC.DLL related issue.

A popular reason that could cause this behavior is when Windows Update already has a scheduled update ready to update the printing component.

Some users who encountered the same error code reported that they fixed the problem by updating their version of Windows to the latest version available. After doing this and restarting your computer, most reported that the CNMSSC.DLL startup error was no longer occurring.

If this scenario is applicable for you, please try to install all pending updates for your operating system Windows and see if this fixes the problem automatically:

  • To open the tab Settings app Windows updatepress the Windows key + R to open a Run dialog box.
  • then write ‘ms-settings:windowsupdate’ inside the text box and press Get in.
  • Once you are inside the screen Windows Updatego to the section on the right and click Search for updates.
  • Then follow the onscreen instructions to install each pending update until your computer is up to date.
  • If you are prompted to reboot before all pending updates can be installed, reboot according to the instructions.

Note: After startup is complete, return to the Windows Update screen to finish installing any remaining updates.

  • After installing all pending Windows updates, you should find that the startup error CNMSSC.DLL stop happening.

If the issue is still not fixed, move on to the next method below.

Remove cnmssc~1.dll from Registry Editor

If you uninstalled your Canon printer software without taking care of all the dependencies, you may start seeing this error message every time you turn on your computer.

This is because there is still a registry key somewhere that tries to call the now missing cnmssc~1.dll file. To fix the problem, you’ll need to find and remove all mentions of cnmssc~1.dll from your Registry using Registry Editor.

Many Windows 10 and Windows 11 users confirmed that this method was effective and that we had previously wrongly uninstalled the Canon printer software.

This is how this is done:

  • press Windows key + R to open a dialog Run. Then write ‘regedit.msc’ inside the text box and press Ctrl+Shift+Enter to open the Registry Editor with administrator access.
  • When the User account control prompted, click on Yes to grant administrator access.
  • Once you’re inside the Windows Registry Editor, make sure the input Equipment is selected in the menu on the left, then go to the ribbon at the top and click Edit > Find.
  • Inside the dialog text box Search, type ‘cnmssc~1.dll’ and press Get in.
  • Once you find the first result, simply press the key Ofthen press Enter to confirm the deletion.
  • Then press F3 to continue the search and continue deleting all keys that contain mentions of the file cnmssc~1.dll until there are none left.
  • Reboot your computer and see if the startup error stops occurring.

If the same type of problem still occurs, move on to the next method below.

Implement a clean boot

You may be encountering the CNMSSC.DLL error code due to some kind of application or service conflict with printer dependencies.

To see if this is the case, you can force Windows to boot with only essential drivers and startup programs. This type of startup (clean boot) will help you identify any software conflicts that may be causing this particular problem.

Here are the steps to perform a clean boot on Windows and see if a third-party service or startup item is causing this startup error:

  • Make sure you’re signed in with a windows account have administrative privileges.
  • press Windows key + R to open a dialog Run, then type “msconfig” and press Get in to open the System Configuration window.

Note: If he User Account Control (UAC) prompts you, click on Yes to grant administrative privileges.

  • inside the window System configurationgo to the tab Services and check the box next to Hide all Microsoft services.

Note: This will ensure that you are not disabling any critical services needed by the operating system.

  • Then disable all remaining services at once by clicking the button disable all.

Note: This operation will prevent third-party services and other non-essential built-in services from causing an application conflict that could lead to the startup error. cnmssc.

  • Once all services have been disabled, click Apply changes, then go to the tab Start and click Open Task Manager.

  • In the Task Manager, go to the tab Status and start selecting each service individually, then click Disable to prevent it from running at startup.

  • Once all third party services have been disabled, close Task Manager and reboot your computer to standby mode clean boot.
  • When the next startup sequence is complete, open the Microsoft Store and see if you can download the app or game that was failing earlier. If not, you can identify which conflicting app or service is causing the error code by systematically re-enabling everything that was disabled, one item at a time, along with frequent restarts until you find which one is causing problems.

In case this method confirmed that no third-party application, service, or process is causing the problem, move on to the next method below.

Start a security scanner scan

If none of the methods so far have been effective in your case, the next step should be to make sure that you are not experiencing this problem due to a virus infection.

To make sure that’s not the case, you can try running Microsoft Safety Scanner from safe mode.

Note: This will ensure that you are using the most powerful virus removal tool Microsoft has ever developed, without worrying about third-party interference.

Here we show you a small quick guide so you know how to run the Microsoft security scanner in safe mode:

  • Turn on your computer (or restart it if it’s already on) and wait until you get to the initial login screen.
  • Once you see the initial login window, click the login icon. switched on (Lower right corner).
  • After you see the power contact menu, press and hold shift while you click Restart for your computer to boot into safe mode.
  • As soon as you do this, your computer will reboot and the new state will be applied.
  • Eventually, your computer will arrive at the Problem solving. When you see it, click Solve problems.
  • Once you are inside the menu Advanced Optionsstart by clicking Setting start from the large list of available options.
  • Inside the menu Start Settingspress F5 to start in safe mode with networking.

Note: It is important that you start safe mode with networkingso that your computer will have Internet access later when we download and use the utility Windows Security Scanner.

  • Once your PC has successfully booted into Safe Mode with Networking, Download the latest version of Microsoft Security Scanner from according to your Windows bit version.
  • Wait until the download is complete, then double-click the file MSERT.exe to open Microsoft Safety Scanner. If you are prompted for notice of UAC (User Account Control)click Yes to grant administrative privileges.
  • Follow the remaining prompts to start a scan with Microsoft SafetyScanner.
  • Now, you should calmly wait until the process is complete.
  • Once the process is complete, restart your computer to start it in normal mode, then see if the operation has allowed you to remove the troublesome startup error.

If this method did not work for you, feel free to move on to the next method below to find out how to deal with the virus infection issue with a third-party utility.

Run a Malwarebytes scan

If the CNMSSC.DLL file is missing from its authentic location and your virus scan reveals suspicious activity, you should implement a security scanner to remove the malware infection.

Based on past experience with similar covert viruses, the most efficient software to use in this case is Malwarebytes. It’s free and will identify most malware that exhibits this behavior.

If the scan completes successfully and the virus infection is removed, restart your computer and see if there is any evidence of the CNMSSC.DLL file at the next system startup.

In the event that this process reveals the CNMSSC.DLL file to be genuine, scroll down to the final potential fix below.

Perform a repair or clean install

If you have come this far and still encountering the CNMSSC.DLL error, it is clear that you are dealing with a serious corruption issue that cannot be resolved in conventional ways.

In this case, the only way to fix the problem is to reset all Windows components to ensure that any instances of corrupted system files are removed.

Most users choose the radical solution: a clean install which gets the job done but also removes any personal data including apps, games, media and documents.

If you want to take a less destructive route that allows you to update your Windows components without affecting any of your personal files (games, applications, photos, documents, etc.), you should perform a repair install. This will allow each of your personal data to be preserved.

In case you want to make a repair facility, you need step-by-step instructions on how to complete this procedure. Thank you for reading us, in our portal you can access more information of interest. We read in a next entry.