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A Single Instance of iTunes

What's this nonsense about only being able to run a single instance of iTunes at a time in an otherwise multi-user environment?

It's silly enough that I can share my tunes across my home network yet I can't share them with someone on the same machine. Despite keeping all my music in /Macintosh HD/Users/Shared/Music, I still have to wander from account to account adding each new CD or iTunes Music Store purchase to each user's library just so that we can share _our_ (defined in the strictest sense) music. Surely your iTunes library on the local machine should show up in my iTunes window just like any other network-shared iTunes library?

You cannot open the application "iTunes" because another user has it open.
Ask the other user to quit the application, then try again.
No, not OK.

Should I mistakenly leave "my copy" of iTunes open and wander off for a bit, there's no music for anyone until my return. No music for you! Nobody but an administrator capable of killing off other logins and processes has the ability to rectify this situation. Should every user really need to be an administrator to truly share this multi-user environment?

Bug or feature? If the former, it'd be a good one to squash. If the latter, why doesn't this feature appear in iPhoto or any of other apps (sans any DRM entanglements)?

writebacks (aka comments & trackbacks)...

Mark wrote

I've noticed this as well, but after some thought put into it (which I doubt you have) it becomes clear that this not possible due to permissions privileges. Maybe another user doesn't want any of your music in his music library? Also, how would you be able to effect a change to his iTunes library file without admin privileges? That's what they are there for- to prevent unwanted changes being made to another persons own preferences.

Chris Clark wrote

A bug.. presumably waiting for a fix.
You can enable multiple iTunes sessions by fooling around with a .plist file or two, as per the instructions at MacOSXHints: http://www.macosxhints.com/article.php?story=20031220135132436 I'm guessing that there is some technical reason they have disabled this; preventing a second user from logging into the iTMS and buying songs on the first user's account, for instance. Hard to tell. One would hope they'll devise a solution and 'LSMultipleInstancesProhibited' will default to 'false' in future versions. Hopefully.

Chris Janton wrote

You can share the same music library with multiple users on the same machine with just a small bit of symbolic linking from Terminal.app

Rufo Sanchez wrote

I think it's the iPod personally - what happens if you leave the iPod plugged in, switch to another user (with a completely different iTunes library, mind you - iTunes defaults to putting your library in your home folder) and open iTunes? My guess is that it would ask to format the iPod and attach it with that users account, leaving one confused user and one unpleased user. This is the only thing that currently makes sense to me. Everything else seems to be related to the iTunes library, which doesn't make sense as iTunes keeps music in the home folder by default right now (unless you've changed the location, but then that's the location for just that user, not everybody). The sharing of libraries between users is a quick fix; see this Apple Support entry for details on that. No idea what happens if two people are accessing the same database at the same time though... (a possible other reason for turning off multiple instances of iTunes?)

Alex Somma wrote

Have you read over your user licence for Itunes. It is quite posible that this problem is covered by that. More often than not user licences only alow you to use one copie of a program at a time. Though, this might seem a litle funy for a program that is esentaily free.

C.K. Sample, III wrote

The Chrisses have it....
Clark and Janton are right. You can get around all this, although it is particularly annoying. And you can have all users on a machine share the same exact library, playlists, etc... The first part you do by following the Mac OS X Hint Clark mentions. My set up: I have a regular old alias inside each user's Music folder to the iTunes folder, which is in another 120GB harddrive. After I set this up, I had to change the permissions of the iTunes folder so that all users have access to all files. I even have the same alias set up on my 12-inch Powerbook, so that when I am signed in to my home network I change the name of the iTunes folder on my 12-inch to iTunesMOBILE and change the alias to the shared iTunes folder from iTunesTOWER to just plain iTunes; then I launch iTunes. This enables me to share all aspects of iTunes, not just between separate machines, but between separate users on separate machines, simultaneously and wirelesly over Airport as well. Works like a charm. ALthough the first couple of times I tried it I made the alias to the Music folder instead of the iTunes folder within the music folder and this SERIOUSLY messed up my machine. Talk about sporadic finder crashes! word to the wise...

ryan nelson wrote

your're running a service on an exclusive port
I don't think this is a license issue. iTunes sharing is a service your computer runs on port 3689, and broadcasts to other network users via Rendezvous. As currently architected, all DRM aside, you couldn't run an additional instance of the iTunes sharing service anymore than several users could run a webserver on port 80 at the same time.

captnswing wrote

no problem, the solution is here
just check my link up there, i wrote it up how to share the itunes library. will also add now how to have multiple instances of itunes running on one machine have fun -captnswing

pat wrote

not a port problem, probably
So I just tested it out. Launch a copy of iTunes with no sharing (looking for or serving up), switch users, launch iTunes, same message. When you switch users your iChat connection is dropped as well. So I would think that any network connections you have are dropped.

Tamara wrote

It's a bug.
I have a friend who works at Apple. It's just something they haven't had a chance to work out.

captnswing wrote

folks, its simple. it can be fixed following http://captnswing.net/howto/itunes

Pai wrote

I have it on good authority that this is simply due to technical issues with Panther's relatively-new fast user switching. Apple engineers were specifically told that there would never be more than one "console" user logged in, and then they changed the rules for 10.3. Some apps didn't get redesigned in time, and this limitation was put in as a stopgap measure. I'm pretty sure Apple isn't trying to be restrictive here.

Tamara wrote

It's a bug.
I have a friend who works at Apple. It's just something they haven't had a chance to work out.

Rael Dornfest wrote

re: K.I.S.S.
I actually don't want to share a music library on the file-system level with others on the same machine; I do, however, want to be able to share their tunes just like I can from any other machine in the house.

Rael Dornfest wrote

re: symlinking and plisting
Thanks for the pointers on how to do this by editing plists or doing some symlinking. I've already solved the issue of sharing a music library (I'm using the Shared directory, as I mentioned), but this is not something mere mortals can/should do.

Rael Dornfest wrote

re: License
This is a multiuser environment. There's no reason I should be prevented from running this one app multiple times. This isn't the case for iPhoto or Address Book. The fact that it's around digital music makes me think DRM issues, but surely these should be fixed/routed around if they prevent fair use of my own legally purchased content.

Rael Dornfest wrote

re: The Chrisses have it....
Interesting workaraounds, but eeewwww!

Rael Dornfest wrote

re: Pai wrote: "stopgap"
Pai, I am indeed hoping this is just a bug as you suggest, to be fixed in a forthcoming update. Interesting, though, that it doesn't affect iPhoto despite the new sharing feature on-board.

Rael Dornfest wrote

re: ports
I believed Rendezvous was capable of broadcasting a service on more than one port (e.g. HTTP on ports 80 and 8080). If so, then the ports issue isn't the problem. If not, wha?

James Duncan Davidson wrote

There can only be one server, but more than one client
There could only be one instance of iTunes attached to the well known port 3689. But that doesn't mean that you shouldn't be able to have multiple clients on the same machine all snarfing content down. Tamara and Pai's comments saying that FUS changed the rules of the game and the apps have to catch up rings true. We'll have to see what happens in iTunes.next.

Jason Shao wrote

Hardware issues
I believe the Apple party line is that since iTunes accesses hardware (e.g. CD burners and iPods) you can't run more than one instance because they haven't sorted out hardware issues - what if one user is burning a CD, and another person wants to also burn a CD? I suppose once they have a chance to engineer in a system to handle conflicts, they'll fix it.

Richard Soderberg wrote

I'd be curious to know if iTunes advertises itself differently on Rendezvous, depending on who you're logged in as; if not, then ignoring that two services can't easily listen to the same TCP port, how could it broadcast the libraries distinctly via Rendezvous such that each could be accessed separately?

captnswing wrote

re: re: symlinking and plisting
rael, you really solved the issue of file-system sharing the itunes library? didn't sound so from your post ("...wandering from account to account..."). have a look at the howto i wrote together, the remedies for the issues you described are there

Rett Nearburg wrote

try using itunes 4.1



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Andreas wrote

I wish iTunes finally starts in Germany so I will be able to explore those "bugs" myself....

Guitar Tabs wrote

Guitar Tabs
I can't post anything my computer crashes all the time :(

Black Horse wrote

iTunes can be a good deal for independent labels and musicians (see side bar) and there's no reason for them to boycott-- labels get a somewhat bigger cut than they would from a CD sale and artists on indy labels get much bigger cut than those on major labels. But most people don't find out about music on the internet, they hear it on the radio (that's why the majors sell 85% of all music). If the major labels can eventually use iTunes and similar internet services to survive, independent labels will stay locked off of mainstream radio. Which is why this is not an anti-Apple page-- we own Macs, we run Panther, and we know how much better Apple's computers are. It's precisely because Apple did such effective design on the iTunes Music Store software that it becomes dangerous. An unusable, unsuccessful music service won't keep major labels in control, but iTunes and copycats might. In practice, iTunes is already a voluntary contribution system -- all of their music is available on filesharing networks. It proves that people will contribute to artists if it's easy. Even more will contribute if the artist gets more than 10%.

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