I just saw this error in my console. I'm not in-game but I don't see anyone saying anything about a problem with the plugin:

Failed to call hook 'CanMountEntity' on plugin 'ManageMini v0.2.6' (NullReferenceException: Object reference not set to an instance of an object)
at Oxide.Plugins.ManageMini.setWire (IOEntity output, System.Int32 pin_O, IOEntity input, System.Int32 pin_I) [0x00000] in <4925850e02e7484bb9bbc40b8d6224d0>:0
at Oxide.Plugins.ManageMini.setWireScheme (BasePlayer player) [0x00052] in <4925850e02e7484bb9bbc40b8d6224d0>:0
at Oxide.Plugins.ManageMini.disableWire (BasePlayer player) [0x00066] in <4925850e02e7484bb9bbc40b8d6224d0>:0
at Oxide.Plugins.ManageMini.setMiniRotation (BaseVehicle mini) [0x00088] in <4925850e02e7484bb9bbc40b8d6224d0>:0
at Oxide.Plugins.ManageMini.fixUpgradeMini (BasePlayer player) [0x001a6] in <4925850e02e7484bb9bbc40b8d6224d0>:0
at Oxide.Plugins.ManageMini.CanMountEntity (BasePlayer player, BaseMountable mini) [0x00095] in <4925850e02e7484bb9bbc40b8d6224d0>:0
at Oxide.Plugins.ManageMini.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x001b3] in <4925850e02e7484bb9bbc40b8d6224d0>:0
at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <31122a27a2414cd799150f8677cf39d4>:0
at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in <0fbce81d88d64454b3e7abb24df7026b>:0
at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <0fbce81d88d64454b3e7abb24df7026b>:0​

I think V3.1 will fix that issue. Test and let me know.

Merged post

I have replicated the error, I think.  The error is created when the turret is removed by any means other than by the player using the command /upgrademini turret remove and an authorized pilot mounts the minicopter pilot seat, which would reset the wiring back to default. Since the turret is not found the error pops up.  I will try to figure out a better means of handling the thrown error. Thanks for letting me know.

Merged post

Fixed in version 0.3.3.  At least error I was able to replicate when an upgrade is removed without chat command ie damage destroy. 

This was 9 months ago. I'm not even using this plugin anymore, but hopefully that will help someone who is using it.