Premiere Pro Import Issue -"We were unable to open the file on disk"

Hi,

I'm having some trouble importing a couple of clips into Premiere. I have imported nearly 1000 clips for a project, but 2 in particular will not upload and being up the error box saying "We were unable to open the file on disk" These 2 files are exactly the same as the rest of the project. I have scanned through similar discussions from last year and tried all suggestions (clearing media cache, updating PP, changing the source of the file) and am hitting dead ends with all of them. Any one able to help?

INFO:

iMac OS High Sierra version 10.13.4

Premiere Pro CC 2019 (completely up to date as of today (18/12/18)

Quicktime file, .mov, 4096 × 2160, Apple ProRes 422 LT (exact same as the other 100s of clips in the project which have imported without an issue)

If anyone could help that'd be an amazing early Christmas present!