iPhoto suddenly won't open certain videos. Getting the following message OSStatus error -101. I'm starting to panic! All videos worked before I started using Photo and none will open in Photo.

iPhoto suddenly won't open certain videos. I'm getting the following message when I click on the videos: OSStatus error -101. They all worked perfectly fine before I started using Photos and the few videos that I shot today are working fine on my phone, yet they will not work in Photos or iPhoto. I'm most worried about the older videos that are no longer on my phone that used to work fine in iPhoto and no longer do. Has anyone else had this problem? Does anyone have suggestions of how I might get the videos to work again or recover them? I'm not all that tech savvy. Thank you!