How can I stop photos library from appearing on my desktop?

Give this a try: boot into Safe Mode according to How to use safe mode on your Mac and test to see if the problem persists. Reboot normally and test again.

NOTE 1: Safe Mode boot can take up to 3 - 5 minutes as it's doing the following; 

• Verifies your startup disk and attempts to repair directory issues, if needed

• Loads only required kernel extensions (prevents 3rd party kernel/extensions from loading)

• Prevents Startup Items and Login Items from opening automatically

• Disables user-installed fonts 

• Deletes font caches, kernel cache, and other system cache files

NOTE 2: if you have a wireless keyboard with rechargeable batteries connect it with its charging cable before booting into Safe Mode. This makes it act as a wired keyboard as will insure a successful boot into Safe Mode.

Does the photoslibrary.photoslibrary contain your photos, or is it an additional library?

If it is an additional, empty library, you may have an app installed, that is needing the Photos.app to add adjustments to photos, and is creating its own, temporary library, every time you are opening the app.

The Photos.app will also create additional libraries, if your own library is in allocation, where Photos cannot work with the library. Where are you keeping your Photos Library usually? In the Pictures folder or somewhere else?

It is suspicious, that the Photos Library is appearing on the Desktop. Are you using iCloud? And is iCloud set to sync the Desktop and Documents with iCloud? Then one of your other devices may have dropped a Photos Library onto the Desktop, where it is not save. A Photos Library must be in o folder that is syncing with some cloud service. The library must not be in a DropBox or Google Drive or iCloud Drive.

I'm not sure what "photoslibrary.photoslibrary" is-- the default is "Photos Library. photoslibrary" Is this what you mean?

The normal location for a Photos Library is in your Pictures folder. Is that where yours is?

Sometimes people mistakenly put the Photos Library in the iCloud Drive folder, but this cannot work. If it gets in there, then it should have the "OH NO" icon

with a slash through the cloud. Again, the Library can't work from here, and it needs to be dragged back to your Pictures folder.

If it doesn't drag there, or if it springs back, then there are problems. Do you have more than one Library? To check, close Photos and option-click on the Photos icon. This brings up the Library chooser dialog

Here you can see that I have several Libraries. The main Library, the one that other apps and iCloud refer to, is the System Library. The designation of System Library is made in Photos' Settings>General. You can see the path to each Library when you click on it.

Does any of this give you a clue about what's going on?

léonie wrote: … A Photos Library must be in o folder that is syncing with some cloud service. The library must not be in a DropBox or Google Drive or iCloud Drive.

A typo correction (or autocorrect correction): "A Photos Library must NOT be in o folder that is syncing with some cloud service…"

Denis Neron wrote: iCloud is not involved in my problem.

But it says "iCloud Drive On." I think léonie and I are wondering if this Photos Library has gotten itself into iCloud Drive. That's why I asked about the Library Chooser. Perhaps you could look and see how many Libraries are listed and what their paths are…

For those keeping tabs on this post, simply reinstalling the MacOS from recovery doesn't work. Tried it last night and issue reappeared right after all login items completed loading up.

I have an open case with Apple (which downloaded diagnostics and sent off to Engineering to address).

4/23 Status update from Apple support: As of right now we are still waiting on more information from the engineers on this case as they are still investigating this issue. There are other people experiencing this same issue and it maybe something resolved with an upcoming update. I do apologize about the inconvenience.

"maybe" is not comforting, but I'm holding out hope.

Davidkor wrote: … rebooting simply recreates the originals

With multiple people here, I'm having a hard time separating experiences. Did you e-start in Safe Mode, or not?            Start up your Mac in safe mode - Apple Support 

Davidkor wrote: …not sure what you mean by "make a new user". in every one of my responses to you, I'm simply replying to your comment. As you can see in the attached image. Where it shows up in this thread is anyone's guess.

I'm sorry--if you click in the upper right underneath the little bell

You can set the order of responses. I use "Newest" first.

The point that I was making is that, when you have a question, it's often better to start a new thread. Very often folks break into a thread, thinking it's the same, when their situation is different. That makes it very difficult, as you said, to keep in mind which situation (iCloud or not, external drive or not, optimize, or not, Mac or iPhone etc) is being discussed.

Does your problem happen if you make a new user? That means make a new User, sign that user into your iCloud account, and see what's different. That lets us know if the problem is with the User account, or something else.

Davidkor wrote: For those keeping tabs on this post,

I haven't been, but it's interesting. photoslibrary is a package, a kind of semi-protected folder, and I think that folders sometimes behave awkwardly in iCloud Drive (though less so recently.) Have you tried opening the package (something you don't do with an active Library!) and deleting interior files, rather than folders? Open the package starting with a right-click.

I have a photoslibrary in my iCloud Drive just to play with, and I haven't had problems with it (except, of course, that it doesn't work at all there!) So I can't really test anything-- I just wondered if this might work…

Davidkor wrote: … The way the threads appear in here lacks full context.

That's because, usually people make a new thread for their own question, rather that saying "I have the same problem, but "

Does this problem happen if you make a new user?

My normal library was in the Pictures folder and working great.

The new one created each day after upgrading to Sequoia 15.4 appear on the desktop and are unusable.

I think that this library was created after creating screen capture.

Denis Neron wrote: …My normal library was in the Pictures folder and working great.

The new one created each day after upgrading to Sequoia 15.4 appear on the desktop and are unusable.

You don't show the iCloud set. Can you open it by clicking on the little > arrow?

Is your Desktop folder listed under iCloud?

I have the same problem, but with 2 photos library files with different names. if I delete the 2 ghost files, empty the trash, and reboot, they appear right after all start up apps have finished loading.