The item %0 you are adding is also part of a project (%1) that is currently under source control. The source-controlled project ...

The item %0 you are adding is also part of a project (%1) that is currently under source control.

The source-controlled project is not under the same root as the project (%2) to which you are adding this item. Therefore you cannot check in the project (%2) later.

If this item is stored at a fixed location for all users, you can use the Exclude from Source Control command so that the rest of the project to be added.