If you get this message, there’s a way to solve it without giving up and having to end up buying something to import your photos from iPhone to the PC.
Go to you’re iPhones settings, scroll down to - Photos - scroll down to - TRANSFER TO MAC OR PC - which most likely is set to - Automatic - all you have to do is switch it to - Keep Originals - and that should solve the problem. To be safe, close the apps you have running by pressing the home button twice and swiping up, then plug in your iPhone cord to the USB of your PC, allow your phone to trust the computer, and choose to imort your photos to computer.
P.S. make sure once it begins to import that your cord doesn’t move around or accidentally unplug, the photos that were importing will still be imported but you will receive the same message again, and will just have fix the cord and re-import the photos that had not been imported (the app will automatically select them for you)
Hope this helps because it certainly worked for me.
Additional information: App used to import - Windows Photo App
Phone - iPhone8
Windows version - Windows 10
Update 2/5/2021 - Helpful Video with Steps: