why wont some .MOV files files open on my macbook air but not on my
Hello everyone
I have 20 .MOV files in a folder saved onto an external hard drive that I filmed on my iPhone only 2 weeks ago they all open perfectly on my 2019 Macbook Air each one shows a thumbnail and opens up in Quicktime and opens in iMovie without a problem. However when I plug the same external hard drive into my Mac and open the folder out of the 20 .MOV files only 5 play show a thumbnail and play perfectly however, the rest have the Quicktime logo and will not open or play at all?
any ideas?
hope you guys can help, I'm tearing my hair out