Linker Tools Error LNK1104

cannot open file 'filename'

This error is reported when the linker fails to open a file, either for reading or for writing. The two most common causes of the issue are:

  • your program is already running or is loaded in the debugger, and

  • your library paths are incorrect, or aren't wrapped in double-quotes.

There are many other possible causes for this error. To narrow them down, first check what kind of file filename is. Then, use the following sections to help identify and fix the specific issue.

Can't open your app or its .pdb file

Your app is running, or it's loaded in the debugger

When filename is your executable's name, or an associated .pdb file, see if your application is already running. Then check whether it's loaded in a debugger. To fix this issue, stop the program and unload it from the debugger before building it again. If the app is open in another program, such as a resource editor, close it. If your program is unresponsive, you may need to use Task Manager to end the process. You might also need to close and restart Visual Studio.

Your app is locked by an antivirus scan

Antivirus programs often temporarily block access to newly created files, especially .exe and .dll executable files. To fix this issue, try excluding your project build directories from the antivirus scanner.

Can't open a Microsoft library file

Windows libraries, such as kernel32.lib

If the file that can't be opened is one of the standard library files provided by Microsoft, such as kernel32.lib, you may have a project configuration error or an installation error. Verify the Windows SDK has been installed. If your project requires other Microsoft libraries, such as MFC, make sure the MFC components were also installed by the Visual Studio installer. You can run the installer again to add optional components at any time. For more information, see Modify Visual Studio. Use the Individual components tab in the installer to choose specific libraries and SDKs.

Versioned vcruntime libraries

If the error message has a versioned Microsoft library such as msvcr120.lib, the platform toolset for that compiler version may not be installed. To fix this issue, you have two options: Upgrade the project to use the current platform toolset, or install the older toolset and build the project unchanged. For more information, see Upgrading Projects from Earlier Versions of Visual C++ and Use native multi-targeting in Visual Studio to build old projects.

Retail, Debug, or platform-specific libraries

The error may occur when you first build for a new target platform or configuration, such as Retail, or ARM64. In the IDE, verify the Platform toolset and Windows SDK Version specified in the General property page are installed. Also verify the required libraries are available in the Library Directories specified in the VC++ Directories Property Page. Check the properties for each configuration, such as Debug, Retail, x86, or ARM64. If one build works but another doesn't, compare the settings for both. Install any missing required tools and libraries.

The vccorlib.lib library

There are no Spectre-mitigated libraries for Universal Windows (UWP) apps or components. If the error message includes vccorlib.lib, you may have enabled /Qspectre in a UWP project. Disable the /Qspectre compiler option to fix this issue. In Visual Studio, change the Spectre Mitigation property. It's found in the C/C++ > Code Generation page of the project Property Pages dialog.

Libraries in projects from online or other sources

If you build a project copied from another computer, the library installation locations may be different. For command-line builds, verify the LIB environment variable and library paths are set correctly for the build. In Visual Studio, you can see and edit the current library paths set in the Property pages for your project. In the VC++ Directories page, choose the drop-down control for the Library Directories property, then choose Edit. The Evaluated value section of the Library Directories dialog lists the current paths searched for library files. Update these paths to point to your local libraries.

Updated Windows SDK libraries

This error can occur when the Visual Studio path to the Windows SDK is out of date. It may happen if you install a newer Windows SDK independently of the Visual Studio installer. To fix it in the IDE, update the paths specified in the VC++ Directories property page. Set the version in the path to match the new SDK. If you use the Developer Command Prompt, update the batch file that initializes the environment variables with the new SDK paths. This problem can be avoided by using the Visual Studio installer to install updated SDKs.

Can't open a third-party library file

There are several common causes for this issue:

  • The path to your library file may be incorrect, or not wrapped in double-quotes. Or, you may not have specified it to the linker.

  • You may have installed a 32-bit version of the library but you're building for 64 bits, or the other way around.

  • The library may have dependencies on other libraries that aren't installed.

To fix a path issue for command-line builds, verify the LIB environment variable is set. Make sure it includes paths for all the libraries you use, and for every configuration you build. In the IDE, the library paths get set by the VC++ Directories > Library Directories property. Make sure all the directories that contain the libraries you need are listed here, for every configuration you build.

You might need to supply a library directory that overrides a standard library directory. On the command line, use the /LIBPATH option. In the IDE, use the Additional Library Directories property in the Configuration Properties > Linker > General property page for your project.

Make sure you install every version of the library you need for the configurations you build. Consider using the vcpkg package management utility to automate the installation and setup for many common libraries. When you can, it's best to build your own copies of third-party libraries. Then you're sure to have all the libraries' local dependencies, built for the same configurations as your project.

Can't open a file built by your project

You may see this error if filename doesn't exist yet when the linker tries to access it. It can happen when one project depends on another in the solution, but the projects build in the wrong order. To fix this issue, make sure your project references are set in the project that uses the file. Then the missing file gets built before it's required. For more information, see Adding references in Visual Studio C++ projects and Managing references in a project.

Can't open file 'C:\Program.obj'

If you see the filename C:\Program.obj in the error message, wrap your library paths in double quotes. This error happens when an unwrapped path that begins with C:\Program Files gets passed to the linker. Unwrapped paths may also cause similar errors. Typically, they show an unexpected .obj file in the root of your drive.

To fix this issue for command-line builds, check the /LIBPATH option parameters. Also check the paths specified in the LIB environment variable, and the paths specified on the command line. Make sure to use double-quotes around any paths that include spaces.

To fix this issue in the IDE, add double-quotes as necessary to the following properties for your project:

  • The Library Directories property on the Configuration Properties > VC++ Directories property page,

  • The Additional Library Directories property in the Configuration Properties > Linker > General property page,

  • The Additional Dependencies property in the Configuration Properties > Linker > Input property page.

Other common issues

Path or filename issues

This error can occur when the library filename or path specified to the linker is incorrect. Or, when the path has an invalid drive specification. Look on the command line or in any #pragma comment( lib, "library_name" ) directive for issues. Check your spelling and the file extension, and verify the file exists at the specified location.

Parallel build synchronization

If you're using a parallel build option, Visual Studio may have locked the file on another thread. To fix this issue, verify the same code object or library isn't built in multiple projects. Use build dependencies or project references to pick up built binaries in your project.

Additional dependencies specified in the IDE

When you specify individual libraries in the Additional Dependencies property directly, use spaces to separate the library names. Don't use commas or semicolons. If you use the Edit menu item to open the Additional Dependencies dialog box, use newlines to separate the names, not commas, semicolons, or spaces. Also use newlines when you specify library paths in the Library Directories and Additional Library Directories dialog boxes.

Paths that are too long

You may see this error when the path for filename expands to more than 260 characters. If needed, rearrange your directory structure or shorten your folder and file names to shorten the paths.

Files that are too large

This error can occur because the file is too large. Libraries or object files more than a gigabyte in size may cause problems for the 32-bit linker. A possible fix for this issue is to use the 64-bit toolset. For more information on how to use the 64-bit toolset at the command line, see How to: Enable a 64-Bit Visual C++ Toolset on the Command Line. For information on how to use the 64-bit toolset in the IDE, see Using MSBuild with the 64-bit Compiler and Tools. Also see this Stack Overflow post: How to make Visual Studio use the native amd64 toolchain.

Incorrect file permissions

This error can occur if you have insufficient file permissions to access filename. It may happen if you use an ordinary user account to access library files in protected system directories. Or, if you use files copied from other users that still have their original permissions set. To fix this issue, move the file to a writeable project directory. If the moved file has inaccessible permissions, run the takeown.exe command in an Administrator command window to take ownership of the file.

Insufficient disk space

The error can occur when you don't have enough disk space. The linker uses temporary files in several cases. Even if you have sufficient disk space, a large link can deplete or fragment the available disk space. Consider using the /OPT (Optimizations) option; doing transitive COMDAT elimination reads all the object files multiple times.

Problems in the TMP environment variable

If the filename is named LNKnnn, it's a filename generated by the linker for a temporary file. The directory specified in the TMP environment variable may not exist. Or, more than one directory may be specified for the TMP environment variable. Only one directory path should be specified for the TMP environment variable.

Help, my issue isn't listed here!

When none of the issues listed here apply, you can use the feedback tools in Visual Studio for help. In the IDE, go to the menu bar and choose Help > Send Feedback > Report a Problem. Or, submit a suggestion by using Help > Send Feedback > Send a Suggestion. You can also use the Microsoft Docs Q&A site for questions, and the Visual Studio C++ Developer Community website. Use these sites to search for answers to questions and ask for help. For more information, see How to report a problem with the Visual C++ toolset or documentation.

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