The model used to open the store is incompatible with the one used to create the store错误

错误信息：

2012-07-24 10:35:19.449 appname[5892:16f0b] Unable to load persistent store at URL 'file://localhost/Users/username/Library/Application%20Support/iPhone%20Simulator/5.1/Library/Keyboard/UserDictionary.sqlite' ({

    metadata =     {

        NSPersistenceFrameworkVersion = 407;

        NSStoreModelVersionHashes =         {

            UserDictionaryEntry = <f0c9025b 602122f9 37a4e274 bdaacec1 b9a66f83 fca5c43b bed5e80a 6baee338>;

        };

        NSStoreModelVersionHashesVersion = 3;

        NSStoreModelVersionIdentifiers =         (

            ""

        );

        NSStoreType = SQLite;

        NSStoreUUID = "82DA18BC-0E80-412F-BDC4-77BA04FFDAF9";

        "_NSAutoVacuumLevel" = 2;

    };

    reason = "The model used to open the store is incompatible with the one used to create the store";
})

查看crash thread,显示在nsentitydescription entityforname: inmangageobjectcontent方法上，推断写sqlite数据库错误，而后在工程里的所有[[NSUserDefaults standardUserDefaults] synchronize];地方打断点顺利找到原因。