Block Notepad

Question

Block Notepad

Nihal Prasad 0

Hi All,

We have requirement from Client that we need to block only JavaScript file (.JS) to be open using notepad.
Can anyone please let me know if this is achievable or not , if yes, how can we achieve it.

Thanks

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Answer 1

Anonymous

Hello,

Thank you for posting in Microsoft Q&A.

Based on the description, I understand your question is related to notepad.

Go to Settings > Apps > Default apps.

Scroll down and click on Choose default apps by file type.

Find the .js file type in the list.

Change the default app to a different program (e.g., a text editor other than Notepad or a custom script that does nothing).

You can also block the execution of JavaScript files using Attack Surface Reduction (ASR) rules in Microsoft Defender

Have a nice day.

Best Regards,

Molly

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Nihal Prasad 0 Reputation points

2025-03-14T15:28:09.6+00:00

Thanks for the response @Anonymous .

But even if we change the default app of .JS file type , user can anytime use "OpenWith" option to open .JS from notepad.

Is there any way we can prevent opening .JS File type from Notepad?
Anonymous

2025-03-20T08:41:57.71+00:00

AppLocker can be used to create rules that prevent specific applications from running:

Open Local Security Policy:

Press Win + R, type secpol.msc, and press Enter.

Configure AppLocker:

Go to Application Control Policies > AppLocker.

Right-click on Executable Rules and select Create New Rule.

Follow the wizard to create a rule that denies notepad.exe from opening .js files.
Nihal Prasad 0 Reputation points

2025-03-20T09:47:59.55+00:00

Thanks @Anonymous

Sorry to say , now requirement has been changed and they are looking to block notepad only on "Downloads" folder under all the user profile folder.
MotoX80 36,291 Reputation points

2025-03-20T12:03:44.22+00:00

Just an observation here... if the user has read access to the files, even if you block notepad there are many other ways to access the content. Open a command prompt and use the "type" command, open a Powershell prompt and run Get-Content. In MSEdge you can just type in the name of a file in the address bar and it will display the contents.

What's to stop the user from copying a file from the downloads folder to some other folder and then opening it?

You might want to provide some background on the root problem that you are trying to solve and see if anyone has an idea to help you.

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Block Notepad

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