if the project is not a big ,
1- change the name of folder project
2- make a new project with the same project (before renaming)
3- add existing files from the old project to the new project (totally same , same folders , same names , ...)
4- open the the new project file (as xml ) and the old project
5- copy the new project file (xml content ) and paste it in the old project file
6- delete the old project
7- rename the old folder project to old name