Thanks a lot for your quick response and the detailed explanation! The more I think about files and its metadata, the observed behavior makes sense to me :D So for creating new files I will definitely change my code to use -writeToURL:options:error:. How big is this file? The files in my app are typically documents like TXT, PDF, MS Word, etc. Therefor the size varies between a few KBs and many MBs. I guess storing such files in NSData would exceed the memory limits pretty fast. Unless you want to spend more time with some research about this topic, I am going to use NSFileManagers -copyItemAtURL:toURL:error: in combination with -setAttributes:ofItemAtPath:error:.

If I pass NO to the atomically parameter the file inherits the NSFileProtectionType. Is it expected/documented that the atomically parameter prevents the inheritance of NSFileProtectionType? Furthermore I have observed a similar behavior with -[NSString copyItemAtURL:toURL:error:]. The copied item does not inherit the NSFileProtectionType of its new parent directory. Do I have to manually change the attribute after the item has been copied?

Hi, sorry to jump into this old thread, but I've a question about the following sentence "By default the data protection value is inherited from the parent directory when you create an item." because as far as I have tested this, it seems to be a wrong assumption. For example I have the following code: objc BOOL success = YES; NSError *error = nil; NSURL *tmpDir = [NSFileManager.defaultManager.temporaryDirectory URLByAppendingPathComponent:@"tmpDir"]; success = [NSFileManager.defaultManager createDirectoryAtURL:tmpDir withIntermediateDirectories:YES attributes:@{ NSFileProtectionKey: NSFileProtectionComplete } error:&error]; NSFileProtectionType tmpDirFileProtectionType = [NSFileManager.defaultManager attributesOfItemAtPath:tmpDir.path error:nil][NSFileProtectionKey]; // tmpDirFileProtectionType == NSFileProtectionComplete - this is OK and expected NSURL *subDir = [tmpDir URLByAppendingPathComponent:@"subDir"]; success = [NSFileManager.defaultManager createDirectoryAtURL:subDir withIntermediateDirectories:YES attributes:nil error:&error]; NSFileProtectionType subDirFileProtectionType = [NSFileManager.defaultManager attributesOfItemAtPath:subDir.path error:nil][NSFileProtectionKey]; // subDirFileProtectionType == NSFileProtectionComplete - this is OK and expected NSString *someStr = @"someStr"; NSURL *someStrFile1 = [tmpDir URLByAppendingPathComponent:@"someStr1.txt"]; NSURL *someStrFile2 = [subDir URLByAppendingPathComponent:@"someStr2.txt"]; success = [someStr writeToURL:someStrFile1 atomically:YES encoding:NSUTF8StringEncoding error:&error]; success = [someStr writeToURL:someStrFile2 atomically:YES encoding:NSUTF8StringEncoding error:&error]; NSFileProtectionType someStrFile1FileProtectionType = [NSFileManager.defaultManager attributesOfItemAtPath:someStrFile1.path error:nil][NSFileProtectionKey]; NSFileProtectionType someStrFile2FileProtectionType = [NSFileManager.defaultManager attributesOfItemAtPath:someStrFile2.path error:nil][NSFileProtectionKey]; // someStrFile1FileProtectionType == NSFileProtectionCompleteUntilFirstUserAuthentication - this is NOT OK and NOT expected // someStrFile2FileProtectionType == NSFileProtectionCompleteUntilFirstUserAuthentication - this is NOT OK and NOT expected I've tested this on an iPhone X with iOS 14.5 and the app does not use the file protection entitlement. Am I doing something wrong?