I had this same problem over and over and finally found the solution. Go into Itunes and turn on Home Sharing. To do this open up ITunes on your PC and go to File --> Home Sharing --> Turn on Home Sharing. You will have to login with your ITunes user name and password, and then once home sharing is on, go back to to the photos app and try the import again. Works like a charm!!!
@ CandiAZ
I just tried it right away. It first looked very promising, the photos app never started so fast to check the content of my iphone and after some while even the import kicked in when all the items were found.
Then after somewhat of 2500 Items out of 9500 my PC started to crash as if I was in the 90ies: one window after the other froze, until my machine came to a complete full stop and frozen dead.
After hard reset the disk scan needed to start a repair.
My RAID5 started the verify job.
Thanks for the very promising tip but I cannot risk that again!
I do not understand the relation of this error to your solution, believe me.. but on the other hand my i7-9800X X299 with all its crazy power should really be able to deal with a simple USB file import.
I cannot afford to try it again.. my heart is still pounding..
this is for sure a serious problem of the iphone software in connection to the Microsoft Software.
Others please post the results of your trials too!