Cant select multiple photos in mac photos ap

You can select multiple albums at once by dragging the cursor across the albums in album view, at least in Photos 4.0 on macOS 10.14 Mojave. I don't remember, if it has been possible in the previous versions of Photos.

For example - the photos from all selected smart albums in the selection rectangle will be exported:

Try the following in order:

1 - boot into Safe Mode, Mac OS X: Starting up in Safe Mode, open the library and try again. Any improvement?

2 - as a test launch Photos with the Option key held down and create a new, test library. Import some photos and test to see if the same problem persists. Does it?

Managing the photo library has been much more intuitive and versatile in the predecessor to Photos, iPhoto. I sincerely hope, Photos will get there soon. It has been improved with every update.