We have a number of HDI systems, which we are forced to keep running on system version 5.0.0-01, because corporate security is only permitting us a one-way, outgoing trust from the device domain to the user domain, with which later system versions cannot function. There is a recurring issue, where whenever the HDI istelf, or just the CIFS service on it is restarted for any reason, all client access to data is lost, with users getting a logon prompt repeatedly popping up on attempts to reach even unrestricted data and the main share listing. When valid credentials are entered, the logon prompt just comes back up, saying that they were invalid. Attempts to reboot HDI or restart CIFS again just seems to reset the issue. Clearing user map cache seems to have no effect. After some hours - the time appears to vary directly with how bad the WAN connection is to the DCs used by the devices - Win 7 connectivity, which uses SMBv2, reestablishes on its own, at which point Win 10 connections using SMBv3 stop returning the logon prompt and begin producing "an extended error has occured". Attempting to reboot or restart CIFS shortly after this change happens just brings Win 7 access back down, but after a wait of a further couple of hours, repeated reboots occasionally do restore Win 10 access. Win 10 access eventually reestablishes, also seemingly on its own. We have opened numerous cases for the issue and are working to allow for system upgrade, but in the meantime, no progrerss has been made and nothing has been found in the logs, other than SMB connections simply fail to show up. Because our configuration is unsupported, it is questionable how extensive an investigation has been performed, however. If anyone has heard of the issue, or has any guidance they can offer on how I might most effectively troubleshoot it, it will be greatly appreciated, as the outages have been quite painful. Thank you.