Photo library won't open on my new MAC; can't open my saved library from old MAC

LarkinM wrote:

#1 - First, I don't have any photos in my new MAC library so why won't it open?

#2 - Second, when I click the option to open another library and select my Photos library from my old mac (on an external hard drive) it says it "cannot create the path" and won't open my old library either.

#1 - Try opening Photos with the Option key held down and select New Library in the next window.

#2 - how is the external drive formatted? What version of Photos crested the library? The library must be on a drive formatted either APFS or OS X Extended (journaled) and both, optimally, with Ownership set to be ignored.