Hello,
Mechjeb is not working for me. I am including a copied text of a portion of the output log, starting and ending with Mechjeb. If more is needed, let me know.

Load(Assembly): MechJeb2/Plugins/MechJeb2

(Filename: C:/BuildAgent/work/d63dfc6385190b60/artifacts/StandalonePlayerGenerated/UnityEngineDebug.cpp Line: 49)

AssemblyLoader: Loading assembly at C:\Program Files (x86)\Steam\SteamApps\common\Kerbal Space Program\GameData\MechJeb2\Plugins\MechJeb2.dll

(Filename: C:/BuildAgent/work/d63dfc6385190b60/artifacts/StandalonePlayerGenerated/UnityEngineDebug.cpp Line: 49)

AssemblyLoader: KSPAssembly 'MechJeb2' V2.4

(Filename: C:/BuildAgent/work/d63dfc6385190b60/artifacts/StandalonePlayerGenerated/UnityEngineDebug.cpp Line: 49)

Load(Assembly): Plugins/MechJeb2

(Filename: C:/BuildAgent/work/d63dfc6385190b60/artifacts/StandalonePlayerGenerated/UnityEngineDebug.cpp Line: 49)

AssemblyLoader: Loading assembly at C:\Program Files (x86)\Steam\SteamApps\common\Kerbal Space Program\Plugins\MechJeb2.dll

(Filename: C:/BuildAgent/work/d63dfc6385190b60/artifacts/StandalonePlayerGenerated/UnityEngineDebug.cpp Line: 49)

AssemblyLoader: Loading assemblies

(Filename: C:/BuildAgent/work/d63dfc6385190b60/artifacts/StandalonePlayerGenerated/UnityEngineDebug.cpp Line: 49)

Non platform assembly: C:\Program Files (x86)\Steam\SteamApps\common\Kerbal Space Program\GameData\TreeLoader.dll (this message is harmless)
Non platform assembly: C:\Program Files (x86)\Steam\SteamApps\common\Kerbal Space Program\GameData\Impossible Innovations\Plugins\ImpossibleInnovations.dll (this message is harmless)
Non platform assembly: C:\Program Files (x86)\Steam\SteamApps\common\Kerbal Space Program\GameData\Kerbaltek\HyperEdit.dll (this message is harmless)
Non platform assembly: C:\Program Files (x86)\Steam\SteamApps\common\Kerbal Space Program\GameData\MechJeb2\Plugins\MechJeb2.dll (this message is harmless)
Non platform assembly: C:\Program Files (x86)\Steam\SteamApps\common\Kerbal Space Program\Plugins\MechJeb2.dll (this message is harmless)
AssemblyLoader: Exception loading 'MechJeb2': System.Reflection.ReflectionTypeLoadException: The classes in the module cannot be loaded.

at (wrapper managed-to-native) System.Reflection.Assembly:GetTypes (bool)

at System.Reflection.Assembly.GetTypes () [0x00000] in :0

at AssemblyLoader.LoadAssemblies () [0x00000] in :0

Additional information about this exception:

System.TypeLoadException: Could not load type 'MuMech.FuelNode' from assembly 'MechJeb2, Version=2.0.9.0, Culture=neutral, PublicKeyToken=null'.

System.TypeLoadException: Could not load type 'MuMech.MechJebModuleStagingController' from assembly 'MechJeb2, Version=2.0.9.0, Culture=neutral, PublicKeyToken=null'.

System.TypeLoadException: Could not load type 'MuMech.PositionTarget' from assembly 'MechJeb2, Version=2.0.9.0, Culture=neutral, PublicKeyToken=null'.

System.TypeLoadException: Could not load type 'MuMech.PositionTarget' from assembly 'MechJeb2, Version=2.0.9.0, Culture=neutral, PublicKeyToken=null'.

System.TypeLoadException: Could not load type 'c__AnonStorey1' from assembly 'MechJeb2, Version=2.0.9.0, Culture=neutral, PublicKeyToken=null'.

System.TypeLoadException: Could not load type 'c__AnonStorey2' from assembly 'MechJeb2, Version=2.0.9.0, Culture=neutral, PublicKeyToken=null'.

System.TypeLoadException: Could not load type 'c__AnonStorey9' from assembly 'MechJeb2, Version=2.0.9.0, Culture=neutral, PublicKeyToken=null'.

(Filename: C:/BuildAgent/work/d63dfc6385190b60/artifacts/StandalonePlayerGenerated/UnityEngineDebug.cpp Line: 49)

AddonLoader: Instantiating addon 'TreeLoaderSpawner' from assembly 'TreeLoader'

(Filename: C:/BuildAgent/work/d63dfc6385190b60/artifacts/StandalonePlayerGenerated/UnityEngineDebug.cpp Line: 49)

AddonLoader: Instantiating addon 'CompatibilityChecker' from assembly 'MechJeb2'

(Filename: C:/BuildAgent/work/d63dfc6385190b60/artifacts/StandalonePlayerGenerated/UnityEngineDebug.cpp Line: 49)

Load(Audio): Squad/Parts/Utility/landingLegLT-1/sounds/sound_servomotor

(Filename: C:/BuildAgent/work/d63dfc6385190b60/artifacts/StandalonePlayerGenerated/UnityEngineDebug.cpp Line: 49)

Platform assembly: C:\Program Files (x86)\Steam\SteamApps\common\Kerbal Space Program\KSP_Data\Managed\Boo.Lang.dll (this message is harmless)
Platform assembly: C:\Program Files (x86)\Steam\SteamApps\common\Kerbal Space Program\KSP_Data\Managed\Mono.Security.dll (this message is harmless)
Platform assembly: C:\Program Files (x86)\Steam\SteamApps\common\Kerbal Space Program\KSP_Data\Managed\System.Xml.Linq.dll (this message is harmless)
[CompatibilityChecker] Running checker version 4 from 'MechJeb2'

You have 2 MechJeb2.dll and one is really old. Delete the one in /plugins ....

C:\Program Files (x86)\Steam\SteamApps\common\Kerbal Space Program\GameData\MechJeb2\Plugins\MechJeb2.dll
C:\Program Files (x86)\Steam\SteamApps\common\Kerbal Space Program\Plugins\MechJeb2.dll