On the login screen, click Manage Connections, then on the dialog box that opens click Delete Existing Project(s) to open the [Select Project] dialog box.
Select the check box(es) of the project(s) you want to delete.
Click OK to validate the deletion.
The project list on the login window is refreshed accordingly.
Be careful, this action is irreversible. When you click OK, there is no way to recuperate the deleted project(s).
If you select the Do not delete projects physically check box, you can delete the selected project(s) only from the project list and still have it/them in the workspace directory of Talend Studio. Thus, you can recuperate the deleted project(s) any time using the Import existing project(s) as local option on the Project list from the login window.