Cannot export video from Photos app

[bigfatipod]

I purchased a new SSD and was attempting to copy my Photos library over to it. I get a message indicating the library could not be copied due to an error (i forget the exact message and will try to recreate it - its a relatively common one on the internet). So my next step was to export all the images and I receive a list of what cannot be copied, due to the following error:
"The export operation failed to create files for the 10 photos listed below:"
When I open them up, they show about 50% of the image but the other have is all green, etc, so I'd say these files are probably corrupted. Luckily, about 7 of them don't matter at all. I deleted them and tried the export again and now have only 3 files that have issue when exporting.

Unfortunately, those remaining 3 files are videos of my baby that I'd really like to keep. I can open them up and watch them in Photos without any issue. I've been unable to drag/drop them to the Desktop or the new SSD (both formatted Mac OS journaled). And if I try exporting the unmodified file, I get the same "The export operation failed to create a file for the photo identified below".

If I get 'package contents' on the Photo app and search within it, I don't find those videos anywhere. I have also tried rebuilding the Photos library.

Mac OS High Sierra 10.13.6
Photos 3.0

Anyone have any advice?

Thanks!

 

[bigfatipod]

Update:
I was able to import into iMovie. once I got it in there, the export went fine... One of videos worked and I am trying the others.

 

[bigfatipod]

So cleaned up all the corrupt files in my Photo library, but I am still getting "
The Finder can’t complete the operation because some data in “Photos Library.photoslibrary” can’t be read or written.
(Error code -36)"
when I try to copy the library to the external ssd.
I can now export all the contents to the external drive without any of the errors, but I really dont wan to deal with importing individual files.

I double checker permissions on the destination drive/folder and everything seems fine (I'm am admin user).
I had a second photos library that I was able to copy to the same destination without any problem.
I had run Disk Utility to repair permissions and that also didn't help.

Can anyone offer any advice?