I have written an OSX app that uses iCloud document storage. Whenever I open it in Mountain Lion (not on Lion), an iCloud window opens that looks like the following:
Putting below codes in your App Delegate lets you bypass that iCloud pop up New Document screen. Tested for High Sierra.
-(void)applicationDidFinishLaunching:(NSNotification *)notification
{
// Schedule "Checking whether document exists." into next UI Loop.
// Because document is not restored yet.
// So we don't know what do we have to create new one.
// Opened document can be identified here. (double click document file)
NSInvocationOperation* op = [[NSInvocationOperation alloc]initWithTarget:self selector:@selector(openNewDocumentIfNeeded) object:nil];
[[NSOperationQueue mainQueue] addOperation: op];
}
-(void)openNewDocumentIfNeeded
{
NSUInteger documentCount = [[[NSDocumentController sharedDocumentController] documents]count];
// Open an untitled document what if there is no document. (restored, opened).
if(documentCount == 0){
[[NSDocumentController sharedDocumentController]openUntitledDocumentAndDisplay:YES error: nil];
}
}