A while back on Twitter, I complained about always seeing the "What's New?" screen in Photos when I launched the app…
So Photos launches to the What's New screen every time I launch it…any way to get that to go away? I tried taking the tour, no joy. pic.twitter.com/ELWXzGexXV
— Rob Griffiths (@rgriff) October 8, 2017
This finally irked me enough that I went looking for an answer…and found one, on only the second entry in my search results.
As the linked answer explains, you can fix the problem by specifying that your Photos library is the System Photo Library, as seen here:
I hadn't specified that my Photos library was the actual System Photo Library, so that button was still active. Once I clicked it, the button grayed out, and on next launch, no more welcome screen!
I think you'll only run into this problem if you (1) migrated an iPhoto library, and (2) kept that iPhoto library on an external drive. In those cases, Photos doesn't set the library as the System Photo Library.
One minor annoyance down, many more to go.