[ERR 22:37:12.389] Exception handling event OnGameSettingsApplied in class TacStartOnce:System.NullReferenceException: Object reference not set to an instance of an object
at Tac.TacStartOnce.ApplySettings () [0x00000] in :0
at EventVoid.Fire () [0x00000] in :0

[EXC 22:37:12.393] NullReferenceException: Object reference not set to an instance of an object
Tac.TacStartOnce.ApplySettings ()
EventVoid.Fire ()
UnityEngine.Debug:LogException(Exception)
EventVoid:Fire()
KSP.UI.Screens.Settings.SettingsScreen:OnApply()
KSP.UI.Screens.Settings.SettingsScreen:OnAccept()
UnityEngine.EventSystems.EventSystem:Update()

KSP.log

I think I found and fixed this, but can't be sure as I can't reproduce the error.

No response, closing.