Moving Photos to External Hard Drive with exFat

Apple is correct. For Photos to work reliably, the external drive must be formatted as Mac OS Extended (Journaled).

To ensure your local copy of Photos contains all images at full resolution, Photos > Preferences > iCloud must be set to Download Originals to This Mac.

If your setting is to Optimize Mac Storage, your local copy contains mostly only small thumbnail previews of your images. If you don’t have the storage space on your MacBook, you can change this setting after moving the library file to the external drive. Be forewarned that if your iCloud Photo Library is sizable, it will take a very long time to download all full-sized images from iCloud.

If and when you need to migrate your photos to a PC there are multiple ways of doing it, but none will retain all the metadata stored in Photos. In any case, you can always re-download your images to your new PC directly from iCloud. They are accessible via any web browser at iCloud.com.

https://support.apple.com/en-us/HT201517

Any external HD that you want to run a Photos library on must be formatted OS X Extended (journaled) with Ownership set to be ignored (preferred).

That's because other formats do not support the library's complex ecosystem of permissions and hard links.

There are other ways, but I suggest moving (copying) your Photos Library file from your MacBook onto the new External Drive. Designate it as the new System Library and make sure the iCloud setting is to download Originals. Quit Photos, but leave your MacBook connected to power and internet overnight. It will be a slow process (days, not hours), but the libraries will sync. To keep an eye on the download progress, you can select the (All) Photos album in Photos app and scroll all the way down. At the bottom of the screen you’ll see a summary showing total number and downloading number, but quit Photos after checking. After the download completed, you can delete the Library from your MacBook, or better yet, copy it to a backup volume, just in case...

The above is basically the instructions from the first link I provided. Here it is again:

https://support.apple.com/en-us/HT201517

Didn’t want to throw too much info at you, but you asked...

Everything sounds fine. After you create a new Library, which you did on the external drive as far as Photos is concerned, it “uploads” images to iCloud to ensure everything is there. This should not create any duplicates in iCloud. When Photos is sure all images are in iCloud, it will start downloading.

One important point after everything is done:

You must always connect the external drive to your MacBook and give it a few seconds to spin up BEFORE you launch Photos. If the external drive with your Library is not connected when Photos is launched, it will create a new library on the MacBook, leading to confusion. As a general practice, the external drive should be connected whenever the MacBook is connected to power, even if you’re not planning to use Photos. This is to ensure everything is always synced with iCloud, which is usually done in the background, when Photos is not launched.

>> I don't believe I can move directly from iCloud to EHD? <<

Photos doesn’t care where the Library file is located. As long as the file on the external drive is designated as the System Photo Library, it will keep it synced to iCloud Photo Library.

>> My setting is for Optimizing MacStorage but Finder shows that photos in my MacBook are 16GB so that must be more than thumbnail previews? <<

Optimization kicks in only when your internal drive starts to run out of storage space. It’s theoretically possible that you always had plenty of room and no, or little, optimization took place. But on a 2009 MacBook? Compare the size of your local library to the size of the iCloud library to see if there’s any difference. The safe assumption would be that not all images on the internal drive are at full-resolution.

>> Also it seems that using my photos on a PC would not be optimal and threfore limits me to staying with MacBook. <<

Most “important” metadata is embedded into the JPEG file itself. Only some Photos-specific info is kept in the app database. This may not be a big issue.

Congratulations! I'm sure you'll agree in retrospect that it wasn't all that complicated, jus a bit nerve wrecking if you haven't done it before...

1a. No, you can't assume that all photos already downloaded at full-resolution. Change that setting.

1b. Yes, all files in iCloud Photo Library are at full size. That's why I said that when iCPL is enabled, it becomes your "master" library. It's always full-resolution, and it always contains all your images, regardless of what and what size you downloaded to your local devices.

2. That's correct. If Photos can't find a library, it assumes none was created and will create a new one. If that ever happens, you'll notice it immediately because it will be empty. Just delete the .library file on the Mac and double-click on the one on the EHD - this re-links it to Photos.

3 (bonus). Keep in mind that iCloud Photo Library is a syncing service, not a backup, or a cloud storage service. When you edit photos on any device with iCPL enabled, the same edits (including deletions, additions, etc) are synced to all other iCPL-enabled devices, including other Macs, iPhones, iPads and iCloud itself. So, never delete local copies on any iCPL device unless you want it gone everywhere.

Glad I was of help on this journey. Enjoy!

Not sure why you’re addressing this to me. The first line of my first post said “Apple is correct. For Photos to work reliably, the external drive must be formatted as Mac OS Extended (Journaled).”

As per previous discussions, I’m assuming you want to stop this process on the MacBook drive because you want the full-resolution images downloaded to the new Photos Library file on the External Drive?

Stopping the current downloads to the Mac drive should have no effect on the iCloud Photo Library contents. It’s the iCloud library that is your “master” and contains everything at full resolution. The warning merely says that Photos will do a bit of cleanup and trash partially-downloaded files ON THE MAC. The master originals in iCloud will remain unaffected - nothing will be removed from iCloud.

I don’t know what else to add, other than Please read earlier replies, among them it says “It will take days, not hours.” so give it some time.

What does it say at the bottom of the All Photos screen?

PS: I don’t understand why you decided to Optimize the external drive library. Wasn’t the whole point of this exercise to have all images at full size?