Can I open a DLL file in Notepad?

You can, but it will appear as unreadable binary 'garbage' code. DLLs are compiled files; you must use a decompiler or resource editor to see the content.

Is it legal to edit DLL files?

Editing DLLs for personal customization or learning is generally fine. However, modifying copyrighted software for distribution or 'cracking' may violate Terms of Service or local laws.

What if I accidentally delete a DLL?

If the file is deleted, the program won't run. You can try to restore it from the Recycle Bin or use Wondershare Recoverit to perform a deep scan for the missing .dll file.

Why can't I save my edited DLL in the System32 folder?

Windows protects system folders. You must save the edited file to your Desktop first, then copy it into the folder using Administrator privileges.

How to Edit DLL Files [2026 Guide]

Amy Dennis

Apr 28, 2026 • Filed to: Recover Files • Proven solutions

Quick Answer: How to Edit DLL Files (2026 Guide)
To edit a Dynamic Link Library (DLL) file safely, follow these steps:

Backup: Always create a copy of the original .dll file before making changes.
Choose Your Tool: Use Resource Hacker for visual assets (icons, strings, menus) or Visual Studio/dnSpy for code-level modifications.
Open & Modify: Launch your editor, open the DLL, navigate to the specific resource (e.g., Icon Group or String Table), and apply your changes.
Compile & Save: Recompile the resource (if using Resource Hacker) and save the file.
Warning: Editing system DLLs can cause Windows to crash or applications to fail. If your system becomes unbootable after editing, use Wondershare Recoverit to create bootable media and rescue your files.

What's the DLL File?

DLL stands for "Dynamic Link Library". Though there are different explanations given from Microsoft, this one could be the better one:
"A Dynamic Link Library (DLL) is a file of code containing functions that can be called from other executable code (either an application or another DLL). Programmers use DLLs to provide code that they can reuse and to parcel out distinct jobs. Unlike an executable (EXE) file, a DLL cannot be directly run. DLLs must be called from other code that is already executing." Dig deep into what is DLL file>>.

Crucial Preparations Before Editing DLLs

Create a Backup: Copy the original .dll file and rename it to filename.dll.bak.
Check File Permissions: System DLLs are "Read-Only." Right-click the file > Properties > Uncheck Read-only to allow modifications.
Identify the Architecture: Determine if the DLL is x86 (32-bit) or x64 (64-bit). Opening a 64-bit DLL in a 32-bit editor will lead to corruption.
Close Dependent Programs: You cannot edit a DLL that is currently being used by an active application. Close the software or use Task Manager to end the process.

When need to edit DLL files?

To edit DLL files is not as easy as you think. They are written in many languages, such as C, C++, C#, Delphi, Visual Basic, Visual Basic.Net, and so forth. So you are required a bit of computer professional skills when editing it.

You attempt to hack it to do something other than what it was intended to do.
You want to extract Icons from the DLLs.
You want to reverse engineer an application.
You are a geek and want to see what it looks like inside.

If you have the reason as above, you can try to edit the DLL file, or you are not supposed to do so. And you'd better ask technicians for help or use professional and easy DLL file editor if you are a computer newbie.

DLL Editor Selection Matrix

Goal	Recommended Tool	Difficulty
Change Icons/Cursors	Resource Hacker	Easy
Edit Text/Menus	Resource Hacker	Easy
Debug/Edit C# Code	dnSpy / ILSpy	Advanced
Reverse Engineering	Visual Studio / IDA Pro	Expert
Repair Missing DLLs	Windows SFC / DISM	Beginner

How to edit DLL files?

There are different ways to edit DLL files. You can download a DLL editor freeware, or get a DLL resource editor, here I strongly recommend you edit DLL files with a program named "Resource Hacker", which is a free and trustworthy DLL editing tool. You can easily download this program from the Internet.

Launch Visual Studio and go to File > Open. Go to the .dll or .exe file you are trying to open, and before clicking Open.

how to edit DLL files

Now you'll be at a screen that has all of the available resources to you. You can edit the DLL file in the window and then save it.

how to edit DLL files

DLL vs. EXE: Understanding the Difference

Feature	DLL (Dynamic Link Library)	EXE (Executable)
Execution	Cannot run on its own; called by others.	Launches directly by the user.
Memory Management	Shared by multiple programs (Saves RAM).	Occupies its own memory space.
Editing Risk	High (One DLL fix can break multiple apps).	Moderate (Only affects one app).
Code Structure	Library of functions and resources.	Contains a main entry point for execution.

Pro Tip for 2026: Digital Signatures & Security

In 2026, modern Windows security (including Windows 11/12) strictly enforces Digital Signatures. If you edit a system DLL or a signed application file, the "Signature" becomes invalid. This may trigger Windows Defender or BitLocker to block the file from running. To test your edited DLL, you may need to enable "Test Signing" mode in Windows via the command: bcdedit /set testsigning on.

Note: Once the DLL file is edited and you decide to recover the original file with the new one, there might be some errors when running the program that contains this DLL file. We highly suggest you save the DLL file as a new and think carefully before editing the DLL file.

DLL Safety & Data Recovery Guide

Risk Level	Scenario	Precaution
Low	Editing a local game DLL	Copy file to a separate folder first.
Medium	Editing App UI strings	Create a System Restore Point.
High	Editing system32 DLLs	Ensure Recoverit is installed to create a bootable recovery USB if Windows fails.

Troubleshooting: Common Errors After Editing DLL Files

"Entry Point Not Found": This happens if you accidentally renamed a function inside the DLL. Ensure all exported function names remain identical to the original.
"The application was unable to start (0xc000007b)": This usually indicates a 32-bit/64-bit mismatch. Ensure your edited DLL matches the application's architecture.
"Access Denied": Windows File Protection (WFP) may be preventing the replacement of system files. You may need to take ownership of the file via the Security tab in Properties.

- 2 minutes to read it.

DLL File Editing & Recovery FAQ

Can I open a DLL file in Notepad?

You can, but it will appear as unreadable binary "garbage" code. Since DLLs are compiled files, they are not intended for plain text editors. To view the actual source code or resources, you must use a specialized decompiler (like dnSpy) or a resource editor.
Is it legal to edit DLL files?

Editing DLLs for personal customization, debugging, or learning is generally acceptable. However, modifying copyrighted software for redistribution or "cracking" typically violates the software's Terms of Service and may infringe upon local digital copyright laws.
What if I accidentally delete a DLL?

If a critical DLL is missing, the associated program will fail to launch. First, check your Recycle Bin. If it's gone, you can use Wondershare Recoverit to perform a deep scan and recover the missing .dll file from your storage drive to restore system functionality.
Why can't I save my edited DLL in the System32 folder?

Windows strictly protects system folders like System32 to prevent malware. You should save your edited file to the Desktop first, then manually move it into the folder using Administrator privileges and confirming the security prompts.