Visual Studio unknown build error. The fully qualified name must be less than 260 characters

Question

I\'m having trouble while building my WPF solution. Everytime I try to build it, I get this error message:

Unknown build error, \'The specified path,

Answer 1

I had the same problem. My checkout path was shorter than the path used on my CI server. It built OK on the CI server, and all my colleagues machines. Our paths are the same length because our company has fixed length user names. I was the only machine that could not build the solution due to long paths.

If you go to these folders:

C:\Windows\Microsoft.NET\Framework

C:\Windows\Microsoft.NET\Framework64

C:\Users\[UserName]\AppData\Local\Temp

Find the version of .NET you are using with your solution, then delete the "Temporary ASP.NET Files" folders from which ever versions you think are effecting your build.

You can delete them all, your next build of a web project might take a little bit longer as there will be no pre-compiled assemblies...

This solution worked for me on a solution containing ASP.NET projects - it wont work on WPF projects that others have mentioned in their answers, unless their solution also contains ASP.NET projects.

Searching for the error string VS gives you brought me here, so I figured it might help someone else, if not the Op with a WPF build issue.

If these fail - you can try searching your solution root recursively for files/folders with paths that are greater the 260, by performing the following:

• Open Powershell

• cd

• cmd /c dir /s /b |? {$_.length -gt 260} > output.txt

This will pipe a list of files with paths > 260 to the output.txt file which will be newly created in the root of your solution.

This will help you find files within your solution that are too long.