FCPX 10.4.2 "not responding"

I'm sorry, I just realized what you were asking Steve. I have no problem accessing FCP and no problem importing HDV video, but when I go to edit it, the thumbnails are "screwed up" with green blanked out portions and when I try to play them by selecting them and using the space bar to play, the wheel of death begins to spin (FCP not responding) and my waiting begins. The video will eventually play, but then if I stop it to place an "in" or "out" or place a favorite, or just stop it and play again, the wheel spins once again. Could it be my Graphics chip set is outdated (Intel HD Graphics 3000) or VRAM not sufficient (I have 512MB)?

Today I did a short video with a Sony HD Handycam recording in AVCHD mp4 to a Sandisk Utra Plus flash drive. FCPX 10.4.2 worked flawlessly with my computer setup. So I am forced to believe that FCPX no longer supports HDV 1080i H.262/mpeg-2 format. Am I correct?

Screen shot of my mp4 editing screen:

I have attached a Drop Box link for download of a sample clip imported into a FCP Library from HDV 1080i (converted to .mov by FCP) (I clipped the audio on this one, so turn your volume down when watching). I also did a screen video (in .mp4) to show you what I am faced with. (This screen video stuff is all new to me, as is this Apple Community site, but everyone has been so helpful! Thank you.) I'm beginning to think my CPU (i5) is insufficient for the new update, but the same thing happens in my MacBook Pro with an i7. As I stated above, when importing an mp4 video, there are no problems at all. Thank you.

Screen video: Dropbox - 2018-05-20 16-48-44.mp4

(.mov clip): https://www.dropbox.com/s/v13029lpqaok75o/2018-05-08%2013_46_06.mov?dl=0

You're right Tom, for some reason my skimmer was off when viewing the thumbnails. When I turned it back on, I can hear it skimming the audio, but no video. I'm importing my videos to FCP libraries in a 3 TB external SSD. I switched to the SSD because I thought my 5 TB traditional spinning HD my be too slow for the update. My video cameras are old technology, a Cannon Vixia HV30 and the one that captured the video you can download is a Sony HVR-HD 1000, bought new (refurbished) about 3 years ago, runs great.

Thank you Tom. I will try converting the files and see how things go. I really appreciate your help. By the way, in an answer to your question on formatting, all my HDs, internal and external, are formatted in Mac OS Extended (Journaled). Thank you.

Mid 2011 iMac

Thank you for all suggestions. I will do some experimenting and see if I can get this resolved.

This is what I am dealing with while trying to edit footage imported from HDV tapes in 1080i: