We have a serious issue with our Azure AD accounts. We use our Azure Ad Accounts (Laptops Azure AD joined) for user authentication on our hardware.
After installing Win 10 1607 on several laptop users were unable to log in with their password or Pin. It only affects some users and we cannot find a pattern or a solution. We have to reset those machines entirely and set them up all over again.
Chiming in here - had PINs stop working after the 1607 update, and tried numerous troubleshooting steps (remove PIN, unenroll device, disconnect/reconnect from/to Azure AD) with MS Tech support - evidently this is a known issue. I ran out of time troubleshooting this mess and just reverted back to the pre-anniversary update. The only last remaining suggested troubleshooting step that I did not perform was to 1) Disable Bitlocker, 2) Clear TPM state 3) Re-enable Bitlocker. If anyone has time to try that, hopefully you can report back here your result!