We are running into some issues where we are checking out a file, opening it, making some changes, then checking it back in, and after getting latest version on another user's machine, those changes aren't there. This brought up a good question I think that I was never sure of. When making changes on a file, are you required to click the save button before checking it in, or does checking the file into the PDM automatically save it?
Checking in the file without saving it in SolidWorks first does not save the changes. You must save first.
Another thing you must remember is that the ability to see the latest version of the file is dependent on the permissions that the user or group has. For example the group that the user belongs to might only be able to see the latest version of the file when it was in the Released State. So if they cannot see a file that is in Work In Progress, they will not be able to see that version at all.