Вы можете использовать каталог библиотеки вместо каталога документов:
// get the library directory:
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES);
NSString *libraryDirectory = [paths objectAtIndex:0];
// make a file name to write the data to using the library directory:
NSString *fileName = [NSString stringWithFormat:@"%@/myfile", libraryDirectory];
// Save data
[myData writeToFile:fileName atomically:NO];