FWIW I have also hit this problem trying to rename .HIF files to .HEIF
In my case I'm shooting with a Sony a7IV and doing nature photography (birds, tiny fast movements), which means a couple of things when interacting with Photo Mechanic:
- I need to shoot in raw+jpeg or raw+heif because the default preview jpegs that Sony inserts into the raw files are so low resolution that you can't compare the sharpness of similar photos.
- It's fantastic that photo mechanic sees two images with the same name but different extensions and then combines them so that I don't have to flip through duplicates...
- But then shooting this way comes at a significant space cost, sometimes ~200GB per day imported, so it's very tempting to go raw+heif to save some space.
- I can't change the .HIF extensions that Sony uses, so I'll have to introduce another tool into my workflow...
But, again FWIW, I think this problem could be easily solvable with some changes to the way the File->Rename Photos process works. I haven't seen the code, maybe it's more complicated than I realize... but I'd be willing to donate some time and work on it if it seems possible