Sync iPhone to Multiple Computers – The information on the iPhone is synced with another user account.

I have recently ventured into syncing my iPhone to multiple computers. I use my home computer to sync pictures, music, videos and contacts to my iPhone; while I use my office computer to sync calendar information. I had originally planned on using my office computer to sync all of my contacts to my iPhone, but then I realized that I typically use my phone for personal use and don’t use it for business that often. Besides, it’s much easier to find contacts in a list of 150 rather than a list of 400.

Anyways, after successfully syncing to my home computer multiple times, I finally decided to bring a cable into my office and sync the iPhone to my office computer as well. Upon plugging it in, I was prompted with this message:

The information on the iPhone is synced with another user account. Do you want to sync this iPhone with the information from this user account instead?

“Merge Info” merges the information on this iPhone with the information from this user account.

“Replace Info” replaces the information on this iPhone with the information from this user account.

Its nice that Apple gives you the option of how you want to handle data from each computer – Either Merge Info or Replace Info. Plus its nice that it lets you pick and choose which information you want to sync from each computer, and the location that you want to sync from (for pictures, music and videos).

29 thoughts on “Sync iPhone to Multiple Computers – The information on the iPhone is synced with another user account.”

  1. I’m glad that you have found this feature useful. I, however, am wondering if I am the only person syncing to multiple machines and NOT finding this useful.

    Here is why…

    I do not want to “Merge Info”. This creates multiple entries which take nearly the same amount of time to sort/delete as inputting in the first place.

    I do not want to “Replace Info” as I might have changed/added information on my iPhone. I do not want to revise these again.

    What I do want….is to “Sync Info”. Basically, to use whichever revision/deletion/addition is newest.

    Not a new idea. Just strikes me as odd that Apple calls the function “Sync” when that isn’t even one of the features.

    I would so like this fixed. Or renamed.

  2. I would like to sync at both my office computer and home computer. Both use Outlook and the same profile (but my home computer is “tunneled” via VPN to the office Exchange Server). Will this process create duplicate entries (because the Apple product sees two different computers) or, since the Outlook account is the same on both computers, will it sync nicely on either computer? [I realize I can test this but thought I would ask in case someone else uses this same type of setup]

  3. Yes, I agree as well… what a HORRIBLE design, merge is NOT how ANY PDA type phone should work. It’s a great OPTION but should not be the only “sync” option.

  4. Hello

    I have my video on one Mac and the Music, calender, contact on another
    When I want to sync my video I do not have the mssage to merge !!
    How do you get that ?
    I have also try AFP this Iphone from my second computer, no way ! connection failed

    Your help will be welcome



  5. Cyril,
    Sorry, I can only respond semi-intelligently to your first question.
    It is impossible to “Sync” any one category, whether it be music, contacts, photos, or even podcasts from multiple machines.
    The software, as it is now written, only syncs one machine’s worth of goodies with your iphone. Period.

    Example: I have my home contacts on my home computer and my work contacts on, you guessed it, my work computer. How do I (without using an external service like .mac) get all of these contacts onto my iPhone?

    As you have stated, you don’t run into this issue as you are copying unique categories from different machines. Try syncing your photos from your home computer AND work computer. No go.

    As far as your second query is concerned: I have heard that iFuntastic is a fairly good way to peruse the files on your iPhone. Sorry, I cannot verify this.

  6. Is there anyway to get the music off my phone onto a new computer? My old laptop that I synced my iphone with had all my music, crashed and I had to buy a new computer and I would really like it if I didn’t have to download a couple thousand songs all over again.

  7. hello, i ve been travelling quite a lot, there for i ve been downloading music from other computers, how can i update my ipod in different itunes without erasing the song i already have?

  8. My question is the same question as Oliver above, my iphone was synch with my other computer, i formated the computer and now i wanna add some music from my laptop, and it gives me that the iphone can be synch with one computer only, any ideas?

  9. it all about copying the itunes libray file to the other machine. The itx file hold all the info on the iphone. This will allow for multiple sync to many different machines


  10. I agree with Greymatters and others who find the behavior annoying.

    A couple of things strike me as ironic.

    1) Apple seems to think nobody should own more than one computer. That’s a strange belief for a computer company.

    2) Prior to the iPhone, I had a Motorola Razr, and I used iSync to sync the contacts and calendars with my two Macs. And it worked as it should. Change it on one computer, sync it with the phone, the change got pushed to the phone. Sync with the other computer, change got pushed to the other computer.

    Maybe Apple made it worse with the iPhone so people will give up and pay whatever Apple wants for their mobile me service.

  11. I have the same question as oliver. I do not understand why I can not just add my music and podcasts from my work computer to my iphone. I hate the fact that I can not delete a podcast without syncing the phone. I should be able to go to the postcast menu and just say edit delete. After I hear last nights news the last thing I want to do is hear it again. We should be able to sync the podcast and add to the list on the phone and not wipe it clear because it is a different system.

    I do not recommend the iphone to friends just because of that.

  12. My main home computer which I sync my iphone has taken a dump and is no longer working. I tried to sync on my wifes laptop which she syncs her iphone on and I cannont. I signed into itunes on her laptop, but it still shows her information.

    Any ideas?

  13. Yeah the sync is crap on iphone. Apple tried to micro control the whole phone. Use iPhonebrowser (google it) to pull the files from the phone into your pc then just push it back properly via itunes. The files and directories on the phone will usually be named all sorts of weird like: NGiLXM would be an album directory containing music with similiar coded names for the songs. Names are relational in the phones database but itunes will see the real name. When you pull the info to the pc, use itunes to Organize the music and it will rename it to proper names. To retrieve folders in iphonebrowser right click a folder and save it locally (Save Folder In) to your pc. Thats for music…not sure about other stuff but should not be too dissimilar.


    Did you ever get a response to this or try it yourself? I’d like to try the same method actually.

    “I would like to sync at both my office computer and home computer. Both use Outlook and the same profile (but my home computer is “tunneled” via VPN to the office Exchange Server). Will this process create duplicate entries (because the Apple product sees two different computers) or, since the Outlook account is the same on both computers, will it sync nicely on either computer? [I realize I can test this but thought I would ask in case someone else uses this same type of setup]”



  15. The only way for Apple to fix this is to put iTunes in the cloud as a web based program. If they did this, you could synch anywhere. If you were to synch on a computer that did not have your music, etc. Then it would only synch what was available.

  16. Multi-computer syncing has been successfully accomplished long before cloud/web based programs were around.

    I don’t want my notes, contacts, and calendar info in some “cloud” somewhere on the wild wild web. I want them on my hand-held device and my computers, where I have control.

    The Palm platform is an excellent example – I’ve always been able to sync my Palms to multiple PCs, and everything is truly syncronized. If there are conflicts in a record, both are copied, and the log documents the issue, which you fix, then re-sync (or not – your choice). iTunes only allows you to choose one or the other, and the changes in the other record are lost. You can’t even cancel to fix it and re-sync.

    To make the iPhone useful for serious business use, as well as personal use, Apple should work with long-time Palm users. Their system may be antiquated now, but it’s always been very effective.

  17. Well, this is one thing that Apple really FAILED on when designing the iPhone. First the inability of the device to sync with multiple computers and email accounts. I.e. I have 3 PCs, two of which use outlook, two separate gmail accounts and several other email accounts. I only want to sync the contacts, fusslessly. NOT possible, ever. You have to manually extract, copy, convert and hack your way into every piece of software on all those machines including the phone in order to achieve what seems to be a basic functionality. With the device itself being great, iTunes is where it fails the most. I want my life under my control, I’m a PC :-)

  18. Even worse: Microsoft has killed the possibility to sync with multiple computers through a bug in the latest version of ActiveSync / Mobile Device Center. This bug, which has been the topic of discussion for months, if not years, causes a sync with a second computer to fail, requiring the user to re-partner his PDA-type device with the first computer and clean up all the double items that are created that way. I used to double-sync trouble-free with my work and home PCs, but no more after the upgrade of ActiveSync. And downgrading is not an option, since the Vista Mobile Device Center is compatible with the latest version only. In fact, it was my need for an alternative for ActiveSync that got me looking for the iPhone option, which I now learn is at least as bad.

  19. Hi FlorisMK –

    I’m able to sync my iPhone to multiple computers – 2 windows PCs and one MacBook Pro. I’m just using iTunes (not Microsoft ActiveSync). Maybe I’m misunderstanding your comment, but hopefully this will help you out.

  20. Hi,

    As I understand this thread, there are issues with syncing to multiple computers if you expect to edit contacts and appointments on all devices. But the point is moot, because my problem is with a HTC Touch Diamond. I was looking into the iPhone as acceptable and multi-syncing alternative, but have been discouraged by the comments in this thread.

  21. Just in case anyone from Apple should read this and take a hint…

    Sync is short for synchronize which means to make two things that are not the same be the same. A sync function should apply moves, edits, adds, and deletes made in each device to the other device in the order in which they were made. MicroSoft ActiveSync does this pretty well so go ahead and copy.

    When I uncheck sync that should mean stop syncing. It does not mean remove everything from one device. Remove is a different function all together and should also be available.

    Merge means make a super-set of the contents of both devices, but do not duplicate any items. Merge is a way to get two things in sync. In cases where each device has the same item (i.e. contact) MicroSoft asks if I want to combine the information from the two items into one item. Now that’s a merge.

    Replace all the contents means take all the old items off of one device and then add all the contents from the other device to the now empty device. You got this one Apple… 1 for 4… good job. However, look at ActiveSync again. When two items appear to be different versions of the same item, ActiveSync let’s me choose which one to sync and which to replace.

  22. One might think the answer to all this is Mobile Me. But its not for I tried that, using my ipad, iphone, macbook pro and dell pc at work, which uses outlook. I ended up having ALL my calendar entries wiped out. Thank God I had backed up the file at work. Now, i sync the iiphone with the macbook pro for music/movies/apps etc and with outlook for calendars/contcts etc. I sync the ipad separately with the macbook pro. The result is that my iphone is always up to date. But there is not way for me to get my calendars/contacts etc to my macbook pro or my ipad. That is extremely annoying. Apple needs to fix that.

  23. Even more fun when iTunes just spontaneously decides your iPhone was synced with another user account when it hasn’t. Now i’m left wondering what changes I’ll lose when I replace my iPhone calendar with my laptop.

    My Palm Pro was smarter than this years ago.

  24. The Sync on two computers seems not to work, so i use the iPhone browser and just add what i want where i want. You can search Google for the free download. The iPhone Browser opens the iPhone and shows all the folders. BE CAREFUL, because u can really mess up your phone if u get careless… Otherwise its a great freeware and a true must have. I even used it to remove unwanted programs and APPS…. Hope this is helpful… :-}

  25. I used to have a Palm Treo and it was amazing for actually syncing data between 2 computers. Then my friend basically dropped it in a pitcher of beer (long story) and I got a Moto Q (which sucked, end of story). Now I have the iPhone 4 and it’s amazing…except for this stupid 2 computer sync issue. I have duplications, deletions, and the worst one of all – some of my contacts have only some of their info deleted. For instance a contact I looked up yesterday had their phone extension…BUT NO PHONE NUMBER!!!

  26. Hi all!

    I’m having the same issue that all of you who were trying to sync with 2 computers were having, except I’m getting this error even though I’m only using one computer!

    My computer had a virus, so we reverted my computer all the way back to a 2 year old back up. After a day and a half of updating, reinstalling, and upgrading, I finally reinstalled iTunes (which had not been installed during or prior to the acquired backup, but had been on this computer for the last 3 months or so). Everything synced fine until I tried to sync my contacts with Outlook, which is what I had been doing just fine prior to the virus. I got the error page that the first message on this thread showed.

    I do not want the hassle of having to correct duplications or deletions and I have new contacts and info that have not been added to my Outlook from my phone. Heck, I’d be happy if I could just tell iTunes to replace my Outlook contacts with my iPhone contacts at this point!!! On top of this, my phone needs to update and I refuse to update it until I can ensure I will not loose or mess up my contacts info by making sure I have a correct and valid back up of my contacts.

    Can anyone help me do a contacts back up (preferably to Outlook from my iPhone 4) that will not make my phone and it’s address book go crazy? I would super appreciate it!

    Thank you!

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