The core becomes unresponsive and Core Console is not loading but displays an error "Oops.. Looks like something went completely wrong" if the Core service was not shut down cleanly and an archive was attached.
Server side:
Service Host Error: Service error while handling request [GET https://localhost:8006/apprecovery/api/core/agentGroups/]: Object reference not set to an instance of an object.
Request Uri: https://localhost:8006/apprecovery/api/core/agentGroups/
Client Address: 127.0.0.1:43556
Identity: NTLM:NT AUTHORITY\SYSTEM
Service: Replay.Core.Management.Agents.Groups.AgentsGroupsManagement
Method: GetGroups
System.NullReferenceException depth 0: Object reference not set to an instance of an object. (0x80004003)
at Replay.Core.Implementation.Agents.Groups.RecoveryPointsBackupGroup.b__9_0(IRecoveryPointsBackupAgent agent) +0x0 60059f3
at System.Linq.Enumerable.WhereSelectEnumerableIterator`2.MoveNext() +0x3f 6001bc4
