why i can not save (import) the project from imovie? Does the movie has to be specific lenght?

Instead of trying to export the project from the project's browser screen, open the project and export from the export button (the little square with the upward pointing arrow in it) in the upper right hand corner of the project's screen. Click on the Export File option in the box that appears.

-- Rich

No, the duration of the project should have no relevance, unless you are talking about a massive movie of 10+ hours or so. What is the duration (running time) of your movie?

Also, more details are needed. Can you explain what steps you are doing to export the project and what happens when you try? Are you getting an error message and, if so, what is the exact text? What versions of iMovie and operating system are you running? How much free space do you have on your internal drive? How much free space do you have on your destination drive for the movie? Does the export issue exist with all projects or just this one?

-- Rich

As a general diagnostic cure, try deleting preferences and see if that solves the export problem. To delete preferences open iMovie while holding down the Option and Command keys and deleting preferences from the box that appears. iMovie will ope in a new blank library. Reopen your old library to get back to your projects. It is a safe procedure that will not cause any loss of data.

-- Rich

Looks like you are good to go. It can take a little while for a two hour movie to fully render, particularly if you exported at the Best quality (pro res) option. Be patient and let the process complete. During the process, you will see a couple of temporary files on your desk top that iMovie places there to help render the movie. The temporary files cannot be played, so don’t click on them. They will disappear once the rendering is done, and will be replaced by the fully rendered movie file.

— Rich

Cool. Glad it worked for you!

-- Rich