Photos library gone after opening an old one

The easiest way to fix this is to create a new photo library

Since your photo library isn't on your Mac anymore, you probably had "optimise Mac storage" turned on for iCloud photos settings.

Since your photo library is on iCloud, all you have to do is sync it with your Mac again. You can turn iCloud photo library on for the old library if you're not against having your old photos on iCloud as well. Keep in mind that the photos on iCloud not being in the photo library won't delete them, it will just re-download them and upload all your old photos onto iCloud.

If you don't want your old photos on iCloud, try the following:

1. hold option and open photos app
2. select "create new library"
3. follow prompts to complete
4. Go to photos menu (top left of screen) then preferences
5. set library as system library (in general tab)
6. go to iCloud tab and turn on iCloud photo library

After doing the above your library should start syncing back onto your Mac from iCloud and your old photos from the other photo library won't upload onto iCloud.

Let me know how it goes!

I missed where you said the library was enabled as the iCloud Photos Library. My error.

What you and do is create a new, empty library (or use the one you have now) and enable it as the iCloud Photo Library. It will then download all of the photos from the library in iCloud and upload any photos from your current library.

If you launch Photos with the Option key held down you should get a window showing all Photos library on your hard drive and any external HDs and the file path to them.

Selecting a library does not remove a previous library. It will still be where it was.

The albums are part of the metadata saved in iCloud.

If these albums are shown on your other devices then they will also come up on your Mac too.

Think of iCloud as the master storage.

All of your devices copy what is saved in iCloud. Any changes you make on a device that is already synced to iCloud will be reflected, but any new devices to connect to iCloud will reflect the information in iCloud, it won't affect what is being shown in iCloud.

if you turn on iCloud photo library for the old photo library (it may not be turned on as you switched photo libraries) it will not affect the current photos on your iPhone.

The old photos will be uploaded onto iCloud and all the albums, etc associated with them which will then sync to the phone.

After the upload is done it will begin downloading all the photos you currently have on iCloud.

To summarise, your photos and albums on your phone will be fine. Syncing your old photos will add on to what is already there, but will not remove anything

It may take a long time to download. Some have reported weeks to download a large library. So keep the laptop plugged into the charger and let it run continuously (you can put it to sleet) when you're not needing it.

If you do not want your old photos on iCloud, yes