Hi,

I get the following output to my console when trying to open my backpack. 

Failed to run a 0.00 timer in 'Backpacks v3.7.2' (NullReferenceException: Object reference not set to an instance of an object)
  at Oxide.Plugins.Backpacks+BackpackManager.GetBackpackPath (System.UInt64 userId) [0x00000] in <e8f857262125495aac78808e00c7ab90>:0
  at Oxide.Plugins.Backpacks+BackpackManager.Load (System.UInt64 userId) [0x00000] in <e8f857262125495aac78808e00c7ab90>:0
  at Oxide.Plugins.Backpacks+BackpackManager.GetBackpack (System.UInt64 userId) [0x00010] in <e8f857262125495aac78808e00c7ab90>:0
  at Oxide.Plugins.Backpacks+BackpackManager.OpenBackpack (System.UInt64 backpackOwnerId, BasePlayer looter) [0x00000] in <e8f857262125495aac78808e00c7ab90>:0
  at Oxide.Plugins.Backpacks+<OpenBackpackConsoleCommand>c__AnonStorey3.<>m__0 () [0x00000] in <e8f857262125495aac78808e00c7ab90>:0
  at Oxide.Core.Libraries.Timer+TimerInstance.FireCallback () [0x00018] in <50629aa0e75d4126b345d8d9d64da28d>:0
(Filename: ./Runtime/Export/Debug/Debug.bindings.h Line: 39)
Failed to run a 0.00 timer in 'Backpacks v3.7.2' (NullReferenceException: Object reference not set to an instance of an object)
  at Oxide.Plugins.Backpacks+BackpackManager.GetBackpackPath (System.UInt64 userId) [0x00000] in <e8f857262125495aac78808e00c7ab90>:0
  at Oxide.Plugins.Backpacks+BackpackManager.Load (System.UInt64 userId) [0x00000] in <e8f857262125495aac78808e00c7ab90>:0
  at Oxide.Plugins.Backpacks+BackpackManager.GetBackpack (System.UInt64 userId) [0x00010] in <e8f857262125495aac78808e00c7ab90>:0
  at Oxide.Plugins.Backpacks+BackpackManager.OpenBackpack (System.UInt64 backpackOwnerId, BasePlayer looter) [0x00000] in <e8f857262125495aac78808e00c7ab90>:0
  at Oxide.Plugins.Backpacks+<OpenBackpackConsoleCommand>c__AnonStorey3.<>m__0 () [0x00000] in <e8f857262125495aac78808e00c7ab90>:0
  at Oxide.Core.Libraries.Timer+TimerInstance.FireCallback () [0x00018] in <50629aa0e75d4126b345d8d9d64da28d>:0
(Filename: ./Runtime/Export/Debug/Debug.bindings.h Line: 39)

does the backpack actually open ?

It does not.

It looks like it's likely the data for that user being corrupted.

Wulf

It looks like it's likely the data for that user being corrupted.

What would you suggest to fix this? It's the same error whether it's me or another player trying to open the backpack. I've reinstalled the .cs file numerous times, restarted the server, and now I'm at a loss. 

The method throwing the error appears to only be capable of throwing an NRE if the _instance variable were null, which could only happen if the Init() method of the plugin failed to be called. I'm not sure how that would be possible. Do you see any errors when reloading the plugin?

Reinstalling the cs file probably won't help, but deleting the config file and letting the plugin regenerate it is worth testing, because config loading happens before Init() is called. Same with the localization file (lang/en/Backpacks). Make sure you back those up first.