[NunyaBzness]

you are not alone. I just had it happen this morning. I was running the 1984 mission so I think it's a game issue, not a mod problem. But I do agree with the above poster, to erase all the old mods

Roger, I erased the override folder and reapplied "the latest" during the uninstall/reinstall procedure.

Since the original post, I also reran the failed mission two other times and archived the output_log.txt file for each attempt. There is a common error theme that seems to be associated with this specific mission, code follows:

Unloading 2 Unused Serialized files (Serialized files now loaded: 0)
IndexOutOfRangeException: Array index is out of range.
  at (wrapper stelemref) object:stelemref (object,intptr,object)
  at VesselBuilder.CreateAndPlaceMeshes (UnityEngine.GameObject vesselTemplate, .Vessel activeVessel, Boolean playerControlled, System.String vesselPrefabRef) [0x00000] in <filename unknown>:0 
  at VesselBuilder.CreateVessel (Int32 vesselID, Boolean playerControlled, Vector3 spawnPosition, Quaternion spawnRotation) [0x00000] in <filename unknown>:0 
  at LevelLoadManager.SpawnShip (Int32 shipNumber) [0x00000] in <filename unknown>:0 
  at LevelLoadManager.LoadLevel () [0x00000] in <filename unknown>:0 
  at MissionManager.LoadTraining () [0x00000] in <filename unknown>:0 
  at CampaignManager.OpenMissionBriefing (Int32 taskforceID) [0x00000] in <filename unknown>:0 
  at CampaignManager.CampaignEngagement (Int32 taskforceID) [0x00000] in <filename unknown>:0 
  at CampaignManager.CheckMapRanges () [0x00000] in <filename unknown>:0 
  at CampaignManager.FixedUpdate () [0x00000] in <filename unknown>:0 
 
(Filename:  Line: -1)

IndexOutOfRangeException: Array index is out of range.
  at PortRearm.SetLoadoutStats () [0x00000] in <filename unknown>:0 
  at PortRearm.InitialisePortRearmRepair () [0x00000] in <filename unknown>:0 
  at Vessel.Start () [0x00000] in <filename unknown>:0 
 
(Filename:  Line: -1)

NullReferenceException: Object reference not set to an instance of an object
  at VesselMovement.Start () [0x00000] in <filename unknown>:0 
 
(Filename:  Line: -1)

The three files were the original (initial campaign); direct to Iceland from autosave; and autosave, kill 2 surface units, direct to Iceland. The enclosed errors are common to all three instances.