Sharing Photos to Toshiba Hardrive

Your pictures are not stored in the Photos app-- that's the instructions for how to work with them. The pictures are stored in the Photos Library, probably called Photos Library.photoslibrary, located in the Pictures folder.

If you have dragged the Photos app to your new hard drive-- trash it! It shouldn't be on the hard drive. You should still have the Photos app in your application folder where it belongs.

So, drag the Photos Library from the Pictures folder to the new drive. I would rename it, like NewPhotos, or something. Then double click NewPhotos. It should open Photos and you should be able to look through it. Look at Imports to see if some of the new pictures are there. Drag one new picture of anything from anywhere onto the NewPhotos Library icon that's now on your hard drive, and make sure it shows up in Photos-- we should make absolutely sure that Photos is looking at the new library.

In fact, go to Photos>Settings>General and look at the path for the Library:

I had renamed my library to remind me what it was for. You can see that mine is in my Pictures folder. Yours should show that your Library is on your new drive. If that's good, tap the Use as System Photo Library. Mine is grayed out, because it is already the System Library.

If you're satisfied that all is well, then go to Settings>iCloud

and turn on iCloud. Make sure everything looks good before deleting the Library on your Mac! In fact, you could again drag that Library to the new drive as a backup, since that one has a new name and is no longer the System Library.

You can see all your Libraries by closing Photos and then option-clicking on the Photos icon. You'll get a dialog like this:

It shows the path to each one and identifies you System Library. The System Library is the only one that connects to iCloud.

Let us know how it goes!

First-- how is your new hard drive formatted-- I'm not sure about "erase and restore." Did you use Disk Utility? This is a mechanical drive, so it should be formatted in  Mac OS Extended Journaled. I've heard that APFS, the newer Apple file system, is a bit slower on mechanical drives. Are you in fact using High Sierra (10.13) as your operating system? How is your internal hard drive formatted?

Do you use iCloud to synchronize your Photos Library on your Mac and phone?

Are you trying to transfer pictures from folders in Finder on your Mac, or are you trying to transfer pictures from the Photos app? What do you mean by "transfer?" If from Finder folders, do you mean that you are dragging them to the drive icon? Or are you trying to drag the Photos Library to the new drive?

If your pictures are maintained in the Photos Library that resides in the Pictures folder on your Mac, then you should be able to copy that Library, probably "Photos Library.photoslibrary" directly to the new drive, if it is properly formatted. Then you can double click on the Library and it should open in Photos.

Is your MacBook used as a portable, moving it from place to place, or is it connected permanently on a desk?

If you use iCloud Photos, and your pictures are stored there, then you will need to make sure that the Photos Library is made your System Library (in Photos>Settings) and connected to iCloud.

Let us know about this stuff, because the method may change a bit depending on your setup....

Same as everything else: drag it to the trash and then empty it.

Just checking in-- how's it working?