What a DLL file is and why you probably don't need to open it
A DLL file (Dynamic Link Library) is a collection of code that programs use to run. Windows itself uses thousands of them. Unlike a document or image, a DLL is not meant to be opened and read the way you would open a Word file or a photo. When you run a program, that program automatically loads the DLL files it needs behind the scenes.
If you have a DLL file sitting on your desktop or in a folder, it usually got there by accident — perhaps from an incomplete software installation, a read that didn't finish, or a file someone sent you. In most cases, the right action is to delete it or move it to the Recycle Bin, not to open it.
That said, there are rare situations where you might need to look inside a DLL to understand what it contains, check its version number, or verify it came from a trusted source. This guide covers those scenarios.
Key Takeaways
- DLL files are code libraries that programs use automatically — they are not documents meant to be opened and read like a text file.
- If a DLL is loose on your computer, it usually belongs in a specific program folder or should be deleted entirely.
- You can view basic information about a DLL (version, publisher, file size) by right-clicking it and choosing Properties.
- To see the actual code inside a DLL, you need a specialized tool like a decompiler, which is only useful if you are a programmer or troubleshooting a specific technical problem.
- Never run a DLL file directly by double-clicking it, and never move a DLL from one program's folder to another without specific instructions from that program's support team.
Check the file properties first — this tells you what you need to know
Before you do anything else, right-click the DLL file and select Properties. The window that opens shows you the file's version number, the company that made it, and when it was last modified. This is usually enough information to figure out whether the file belongs on your computer.
Look at the Details tab. If the file is from Microsoft or from a program you recognize and use, it probably belongs there. If the publisher field is blank or shows a name you do not recognize, the file may be unwanted or corrupted. In that case, move it to the Recycle Bin.
The Properties window also shows you the file path — the folder where the DLL is located. If it is in a program's installation folder (usually under Program Files or Program Files (x86)), it belongs there and should not be moved. If it is loose on your desktop or in your Downloads folder, it does not belong there.
View the file contents with a text editor if you need to see raw code
If you absolutely must look at the code inside a DLL, you can open it with a text editor like Notepad. Right-click the DLL file, select Open with, then choose Notepad. The file will open, but most of what you see will be unreadable — a mix of actual code and binary gibberish.
This approach is only useful if you are looking for a specific text string (like a version number or a company name that might appear in plain text) or if you are a programmer who understands how to read compiled code. For most people, this produces nothing useful.
Do not try to edit a DLL file in a text editor. Changing even one character will break the file and any program that depends on it.
Use a decompiler to see readable code — only if you are a programmer
A decompiler is a specialized tool that converts the compiled code inside a DLL back into something closer to human-readable form. Common decompilers include dnSpy (free, open-source) and ILSpy (also free). These tools are designed for programmers who need to understand how code works or troubleshoot problems.
If you are not a programmer, a decompiler will not help you. The output is still highly technical and requires knowledge of programming languages and how software architecture works. Downloading and installing a decompiler just to peek at a DLL is unnecessary and introduces the risk of downloading malware if you use an untrusted source.
If a software support team has asked you to examine a DLL with a decompiler, they should provide you with the specific tool and instructions. Otherwise, you do not need one.
Find out where a DLL belongs and put it back in the right place
If you found a DLL file outside of a program folder and want to know where it should go, start by searching for the filename online along with the program name. For example, if you have a file called msvcr120.dll, search "msvcr120.dll Windows 11" to find out what it is and which program uses it.
Once you know which program owns the DLL, check whether that program is installed on your computer. Open the program's installation folder (usually Program Files or Program Files (x86), then the program name). If the DLL already exists there, you can delete the loose copy. If it does not exist there, the program may be corrupted or incomplete, and you should reinstall it.
Never manually copy a DLL from one place to another unless you have specific written instructions from the program's support team. Putting a DLL in the wrong folder or in the Windows system folder can cause serious problems.
Recognize when a DLL might be malware
Malware sometimes disguises itself as a DLL file. If you found a DLL in an unexpected location (like your Desktop or Downloads folder), especially if it came from an email attachment or a read link, treat it with caution.
Check the Properties window and look at the publisher field. If it is blank, or if the name does not match any program you recognize, do not open it with any tool. Instead, move it to the Recycle Bin when ready. If you are concerned the file might be malicious, you can upload it to VirusTotal (virustotal.com) — a free scanning service that checks files against dozens of antivirus programs — before you delete it.
Never run a DLL file by double-clicking it. DLL files are not executable programs and should not be launched directly. If something tries to get you to double-click a DLL, it is almost certainly malware or a scam.
Troubleshoot a missing DLL error message
If a program stops working and shows an error message like "DLL not found" or "Cannot find [filename].dll", the program is looking for a file it needs and cannot locate it. This usually happens after a failed installation, a Windows update, or accidental deletion.
The fastest fix is to reinstall the program. Uninstall it completely (Settings > Apps > Apps & features, find the program, click it, then Uninstall), restart your computer, then read and install the program again from the official website. The installer will place all the DLL files in the correct locations.
If reinstalling does not work, search the error message online along with the program name. You may find that a specific Windows update or a missing component (like the Visual C++ runtime) is the cause, and the solution will be specific to your situation.
Frequently Asked Questions
Can I delete a DLL file I found on my computer?
If the DLL is in a program's installation folder, do not delete it — the program needs it to run. If it is loose on your Desktop or in Downloads, you can safely delete it. If you are unsure, check the Properties window to see which program owns it, then decide whether that program is installed and working correctly.
What does it mean if a DLL file has no publisher listed?
A missing publisher field usually means the file is old, unsigned, or potentially unwanted. If it is in a program folder and the program works fine, it is probably just an older file. If it is loose on your computer, move it to the Recycle Bin.
Is it safe to read a DLL file from the internet?
No. Downloading DLL files from random websites is a common way to get malware. If a program is missing a DLL, reinstall the program from the official source instead. If a support team tells you to read a specific DLL, verify the link comes from the official website or a trusted source.
Why does Windows need so many DLL files?
DLL files let multiple programs share the same code, which saves disk space and makes updates easier. Instead of every program including its own copy of common functions, they all use the same DLL. This is why Windows itself contains thousands of them.
What should I do if a program keeps asking for a missing DLL?
Reinstall the program completely. Uninstall it, restart your computer, then install it again from the official website. If the problem continues after reinstalling, the program may be corrupted or incompatible with Windows 11, and you may need to contact the publisher's support team.