Ronald is having problems migrating his photos from Picasa to Google Photos. Leo says that PicasaWeb will eventually become Google Photos. The chatroom suggests going back to Picasa version 3.8, and then let Picasa update itself. But Leo says that getting software from a third party is a dicey affair. So if Ronald can get it directly from Google, then he's in good shape. Google doesn't say that Picasa is compatible with Windows 10, and it may not be. Leo suspects that the compatibility issue could be with Windows Edge, their new browser.
There's a forum post on this issue at productforums.google.com.