Thank you for your contacting us with the issue you are faced with.
The reason for it is that some files are missed locally in the project folder. There are two ways to solve the issue for the project:
- you can re-create a project from the same Organization;
- please open the project folder on your disk, go to the 'src' folder -> 'classes'; check if each of the classes has an appropriate '*.cls-meta.xml' file; when you would find such classes, please open the *.sfproj file from the same project folder and delete entries related to the classes which have missed '*.cls-meta.xml' files; if all the classes have appropriate '*.cls-meta.xml' files, please check the same for triggers; after this open your project in TWS again.
I kindly ask you to let us know about the result of these actions.
If you have any additional questions, please contact me. I will be happy to assist.