imovie installation
i download the imovie from apple support, because i can't download the latest iMovie version due to my Mac OS (mine is still in OS Sierra, haven't update it). After the download done, i click the file to installing it to my Mac, but when i open it, there is this (picture bellow) pop up and i can't continue to the next step.
why it happen? can i still install iMovie on my OS sierra ? How to solve this?
Thanks
MacBook Pro