@morim hi!
You performed the saving p***edure with the right steps.
Firstly carry out the command 'save' on SW or AR, then save the topology project on eNSP.
If you are really sure that you didn't modify this project later, I advise you to create a new project and do the saving p***edure. After that, you can remember the modification date and time.
You can get in the Windows folder, so next time when you open that project and find it had been modified, you can compare the modification date. If it is the same as your last one, modify it. 
P.S.: becasue in another post you mentioned more than one user is using eNSP on your PC, maybe someone else modified your project. 