I am using UIDocumentMenuViewController to allow the user to select the type of cloud service where they want to save a file generated in my app. When the user picks iCloud Drive as a destination, the UIDocumentPickerViewController is shown with a spinning wheel in the middle and after approx. 30 seconds dismisses without performing any action. Tested with two devices, same problem appears on iPhone 6+ and iPad Pro. Simulator works fine. If the user selects another service (OneDrive, Google Drive, DropBox), everything also works fine.
iCloud Drive is allowed on the device and the problem does not repro on a simulator. iCloud Drive app works normally on these devices. xCode 8.3, iOS 10.3 beta3 both. I tried wifi on and off, no difference. No message in the xCode debug window when this happens. Reproduces every time.
Any ideas?
Thanks,
Mirek
Edit: Looks like I can repro the same problem if I try to export image from Photos app.