Visual studio doesn't support specific csproj file

The error doesn't say that Visual Studio doesn't support .csproj files at all, it says it doesn't support a specific project type in that particular project file. This means this either isn't your project as you claim, or you are trying to build it on a different machine from the one used to create the project.

Visual Studio uses various elements in a .csproj file to determine its project type. See How do you tell the Visual Studio project type from an existing Visual Studio project and What is the significance of ProjectTypeGuids tag in the visual studio project file. It does this so it knows how to compile your project, what properties tabs to show, what context menu options should be available and so on.

Certain project types can cause this error. Usually they require some kind of SDK to be installed on the machine used to open or build the project.

You should search the web for the GUID mentioned in the error message you show (the value after o1=). You can also open the project file in a text editor and find the <ProjectTypeGuids> elements, which contains comma-separated project type GUIDs.

Then search the web for those GUIDs to find out which SDK or tool you need to install in order to be able to open or build the project.

If you paste the specific GUID from your error message in your favorite web search engine, you'll find Problem solved: Visual Studio / There is a missing project subtype. Subtype: '{82b43b9b-a64c-4715-b499-d71e9ca2bd60}' is unsupported by this installation., where it is mentioned you'll need to install the Visual Studio 2013 SDK. This means that in this case, your project is a Visual Studio 2013 extension.

This is what documentation is for. You should at least put a ReadMe.txt file in your project directory, explaining what the prerequisites for building a project are, especially when it won't open or build with Visual Studio out of the box.


I had this issue when I used Update 5 for VS 2013.

For me I had to click ok and read the next few steps, that popped up. I was initially clicking cancel.

On mine the project was missing Web Tools, so had to reinstall those and once done it was working.

Hope that helps someone.


This issue also appears when trying to import an ASP.Net project into Visual Studio 2015 Express for Desktop, and can be solved by simply downloading and installing Express 2015 for Web - or by using Visual Studio Community/Standard.