Import DV tape to imovie 10 stops

You described the exact problem that I'm experiencing while trying to import digital video from my Sony DCR-TRV720 Digital Hi8mm Handycam. Except that mine consistently terminates the import at roughly 3 minutes. Like your experience, the import window continues to play the incoming digital video, but it pauses the import. I'm also having a problem with the softkeys on the import window (<< > >>). They are greyed out and inactive. When I select the import button in the lower right screen, the softkeys change to << || >> , and it starts importing. When I checked 30 minutes later, the softkeys had reverted to << > >> indicating that the camera was paused, when in reality it continued playing and just the import function aborted so that iMovie stopped capturing the incoming video. I have over 2 Terabytes free on the internal drive where my iMovie library sits, have 20Gigs of RAM, and a MacPro Tower with Dual Quad Core chips, running 10.10.5 and iMovie 10.0. I'm downloading 10.1 now, but based on your post, I doubt that will help. It has been awhile since I imported from this camera, but it worked flawlessly the last time I did it with an earlier version of OSX and iMovie.

Correction...In my case, the import says it is "Recording" the entire time, but when I close the import window, I find that it consistently only saved the first 1.9 minutes...the rest of the clip doesn't get saved.

I have this same problem importing Digital8 tape from Sony DCR-TRV140. I've imported 7 tapes with iMovie 10.1.1. Four of them imported fine. The other three (#3, 4 and 7) stopped importing after 1-5 minutes even though everything appeared as if they were importing. Anyone have an answer?

I had a similar issue and found an obscure mention in this apple support post If iMovie doesn't recognize or control your camera or camcorder - Apple Support that might help solve the issue:

Make sure the date and time on your camera are set correctly. If the camera uses a backup battery to prevent the date and time from resetting, check this battery to make sure it is still good. See iMovie: Automatic Scene Detection Requires That Camera Clock Be Set Properlyand your camera's documentation for more information.

I found that my clock battery had indeed died and there was no date set. Once I set the date properly, all my captures worked flawlessly. It's worth a look.