UUID mismatch detected with the loaded library

I get a “UUID mismatch” warning at the console when I try to build and run my app on my iPhone.

warning: UUID mismatch detected with
the loaded library – on disk is:

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  • Anyone has this issue and managed to resolve the warning ?

    14 Solutions Collect From Internet About “UUID mismatch detected with the loaded library”

    Uninstalling and reinstalling both the iOS on the device and the SDK did not fix this for me. The only way I was able to get around this issue was by deleting the DeviceSupport files for the 4.2.1 iOS version, which can be found at:


    After deleting the files and restarting Xcode, I plugged in my device and was prompted to restore the symbol files from the device itself – it took about 5 minutes and after this, everything was back to working perfectly.

    As Eric mentioned, this is due to the libraries on the phone being different to those in XCode.

    I came across this issue when I try to debug an app from Xcode using:
    iPhone: iOS 4.2 beta 2
    XCode: iOS SDK 4.1

    However, if I try to debug using XCode with iOS SDK 4.2 beta 2, then it works fine.

    From this, I conclude that the SDK in XCode must match the version of iOS on the phone for debugging to work.

    Ensure the two match and you should be able to debug your app.

    I tried the following

    CLEAN ALL – didnt work



    Plug out phone

    Delete Symbol files folder

    /Developer/Platforms/iPhoneOS.platform/DeviceSupport/4.2.1 (8C148)

    Restart xcode

    plug in phone

    Organizer pops up with message about Unknown IOS detected

    HIt Ok to collect

    Takes about a minute.

    the folder is recreated

    /Developer/Platforms/iPhoneOS.platform/DeviceSupport/4.2.1 (8C148)

    App deployed to device fine after.

    I took the folder from Trash for
    /Developer/Platforms/iPhoneOS.platform/DeviceSupport/4.2.1 (8C148)
    and compared it in Deltawalker
    to the new version of

    /Developer/Platforms/iPhoneOS.platform/DeviceSupport/4.2.1 (8C148)

    and only timestamp differences. The number of files and size of each was identical.

    Theres 380 files in 
    /Developer/Platforms/iPhoneOS.platform/DeviceSupport/4.2.1 (8C148)


    I had downloaded the GM seed of Xcode and iOS 4.2 and tested on another phone.

    My IPhone 4 I upgraded from ITunes like a normal customer.

    Then tried to deploy my app from this GM seed version of Xcode to public released version of iOS 4.2.1.

    If you have Spire installed and you updated to 5.0.1 you need to uninstall Spire or update dyld_shared_cache which Spire is using…

    Spire dyld cache is at /var/spire. You need to extract cache appropriate to your current firmware from ipsw. πŸ™‚

    Completely uninstall the development tools with:

    $ sudo /Developer/Library/uninstall-devtools --mode=all

    (obviously change the path if you installed it somewhere besides the default location). After you install development tools, you should restart your machine. Now reinstall the development tools. This solved this problem for me.

    I tried restoring my device before I reinstalled the development tools and it didn’t solve anything. If reinstalling the development tools doesn’t solve this, I’d probably try restoring your device. Hope that helps someone.

    The current final SDK is only 4.2 while the iOS out in the wild on the devices is 4.2.1. When you first plug in your device in XCode, the Organizer window will collect the debug symbols for your device. If you need to do this again, you can explicitly delete the /Developer/Platforms/iPhoneOS.platform/DeviceSupport/. Funny thing is that occasionally you still get those annoying “Unable to find symbols” error. But at least you’ll be able to debug on device now.

    Hey thanks! I got it working.
    * Using Organizer I reflashed the firmware

    • In Organizer, enable the phone (right click -> Add device….)

    • Close XCode

    • Delete the $project/build/*

    • Delete /Developer/Platforms/iPhoneOS.platform/DeviceSupport/4.2.1

    • Restart XCode

    • Go to organizer and agree to let it download what it wants

    • In Organizer, again right click -> Add Device….

    • Updated Code Signature

    • command + Y

    It debugged just fine after this.

    Thx to all who input πŸ™‚

    It’s benign; don’t worry about it. The message is telling you that a library on the device isn’t exactly the same as a library in the SDK, but the difference between the libraries in this case isn’t one which has any visible impact.

    If you unplug the device from mac, run the app on device. The app works except you won’t be able to utilize console to debug any problems on device. After searching for answers on developer forums, it is a very common problem among developers. However, there is no known solutions except a few possible tips.

    This is an answer from another forum, and IT WORKS! I think it was from webbuilders.com??

    Go figure???

    access this URL for a good description;

    I believe this happens when the when Xcode/iPhone SDK is not up to date with the device’s installed frameworks. Make sure the device software is up-to-date and install the latest version of Xcode/iPhone SDK – worked for me.

    I had this problem also.

    All I did was Quit XCode, Interface Builder.
    Started XCode, re-opened the project.
    Clean All Targets.
    Debug on my iPad in this case worked.

    I know this is an old post, but maybe my solution will help others as I recently experienced this problem.

    I recently upgraded to the iOS SDK 4.1 Beta 3 by downloading the SDK and Xcode updates. After installing this I got the same error as the original poster. Turns out to fix this I simply had to download and install the corresponding iOS version on my iPhone.

    After I installed iOS Beta 3 on my iPhone, restored the phone, recompiled and ran, everything was back as it was.

    For the benefit of anybody who, like me, finds this question through Google, I started receiving this message in the following circumstances:

    1. I had been developing an app using a provisioning profile tied to my personal developer program account;
    2. I switched the app to use a provisioning profile tied to a different developer program account (the client for whom I was developing finally got their account set up).

    The fix that worked for me was to quit Xcode, trash the build directory for the project, then restart Xcode and rebuild. I suspect a “Clean All” from within Xcode might also have worked, but I didn’t think of that until afterwards.

    According to the comments below, “Clean All” won’t work after all.

    I don’t think this is necessarily benign as suggested and the selected answer doesn’t address how to stop the warning. The following should stop the warning:

    1. Unplugging iPhone or iPad from Mac
    2. Quit Xcode
    3. Delete Builds directory
    4. Launch Xcode, plug in iPhone and try again

    YMMV, but this worked for me.