access to files

I have a problem where numerous users are accessing files. Only ever one user can ever edit the project file which is accessed and the rest seem to only have read only which is a pain if someone opens the master programme as all the sub projects are read only.

Can this be changed to enable multiple users to change the project files and if so how is it done.

All other MS stuff does this so i would assume project does only I’m not familiar with it.



thanks