Working on a project at the same time as your colleagues is a feature that is enabled by NVivo Server. To continue to work on your project in this manner after the trial license has expired, you will need to purchase a full NVivo Server license.
If you choose to not purchase a full NVivo Server license, before the expiry of the trial NVivo Server license it is recommended you make a standalone (non-Server) copy of your server project. However, your server project must not exceed the maximum size for standalone projects. For NVivo 10 the project size limit is 10GB whereas for NVivo 9 it is 4 GB. Refer to the link below for instructions about how to copy server projects:
Can I copy a server project to my computer?
If you don’t purchase a full NVivo Server license but your client NVivo license is valid you will still be able to access and work with standalone (non-Server) projects.