Natron accessing, but not reading image data, from external hard drive

Using Windows 10, Natron can read images just fine from my internal drive C: but I was running out of space and moved all the files to an external hard drive called E:.

In Natron, when I press R to read the file, I can navigate fine to E: and all the way down through the subfolders to the image I want to load. But when I load it, the filepath gets populated as you’d expect but no image is loaded (the mostly-black viewer reports 0x0 pixels). Copying the same file somewhere on C: and retrying works fine and the image is loaded.

I’ve looked at the sharing permissions on E: and from what I can tell, everything is shared openly. What am I missing?

Thanks in advance!