Running on 64 bit Windows with 32 GB RAM 
Version: v1.15.3 (Stable)8/6/2021 1:49:25 PM: Critical error occurred
System.NullReferenceException: Object reference not set to an instance of an object.
   at UsefulStuff.ItemClimbingPick.<>c__DisplayClass1_1.<OnHeldIdle>b__0(Entity e)
   at Vintagestory.GameContent.EntityPartitioning.WalkEntities(Vec3d centerPos, Double radius, ActionConsumable`1 callback)
   at UsefulStuff.ItemClimbingPick.OnHeldIdle(ItemSlot slot, EntityAgent byEntity)
   at Vintagestory.Client.NoObf.SystemMouseInWorldInteractions.OnGameTick(Single dt)
   at Vintagestory.Common.EventManager.TriggerGameTick(Int64 ellapsedMilliseconds, IWorldAccessor world)
   at Vintagestory.Client.NoObf.ClientMain.MainRenderLoop(Single dt)
   at Vintagestory.Client.NoObf.ClientMain.MainGameLoop(Single deltaTime)
   at _eAYXniWl7YYoizkDdY8EDX2NUGf._naTl4w2UkJuDlsP9uyhAhjkhAvy(Single )
   at _0h7dYtC5OxgFq3Dhnj2p0gxEXO3._7siDwGtIPuCnT2TllZ2WXtr1bsM(Single )
   at _0h7dYtC5OxgFq3Dhnj2p0gxEXO3._YznPHQWtIAwbLwxdlknpXY2Mrsm(Single )
   at Vintagestory.Client.NoObf.ClientPlatformWindows.window_RenderFrame(Object sender, FrameEventArgs e)
   at System.EventHandler`1.Invoke(Object sender, TEventArgs e)
   at OpenTK.GameWindow.RaiseRenderFrame(Double elapsed, Double& timestamp)
   at OpenTK.GameWindow.DispatchRenderFrame()
   at OpenTK.GameWindow.Run(Double updates_per_second, Double frames_per_second)
   at _Km7YT9SY1sKIj5UBhEpQfHc3XzB._u0WbDJ5hzkzp3qHp31dGQ3NRIqJ(_EyrNhzlOC9XfxRuKJ1Vc8VeXIpA , String[] )
   at _pFLYUi2IEGEC895yDwFlhWqtVoD._u0WbDJ5hzkzp3qHp31dGQ3NRIqJ(ThreadStart )
-------------------------------

Event Log entries containing Vintagestory.exe, the latest 3
==================================
{ TimeGenerated = 8/4/2021 9:15:19 PM, Site = , Source = Windows Error Reporting, Message = Fault bucket 2147604166200357643, type 5
Event Name: RADAR_PRE_LEAK_64
Response: Not available
Cab Id: 0

Problem signature:
P1: Vintagestory.exe
P2: 1.15.3.0
P3: 10.0.19041.2.0.0
P4: 
P5: 
P6: 
P7: 
P8: 
P9: 
P10: 

Attached files:
\\?\C:\Users\geoff\AppData\Local\Temp\RDR34B4.tmp\empty.txt
\\?\C:\ProgramData\Microsoft\Windows\WER\Temp\WER3513.tmp.WERInternalMetadata.xml
\\?\C:\ProgramData\Microsoft\Windows\WER\Temp\WER3572.tmp.xml
\\?\C:\ProgramData\Microsoft\Windows\WER\Temp\WER35FC.tmp.csv
\\?\C:\ProgramData\Microsoft\Windows\WER\Temp\WER369A.tmp.txt

These files may be available here:


Analysis symbol: 
Rechecking for solution: 0
Report Id: 2f747b3d-9d4c-4912-af0a-f7fbe4dc64f4
Report Status: 268435456
Hashed bucket: 15a8c3a1201edd894dcdd29c5485730b
Cab Guid: 0 }
--------------
{ TimeGenerated = 7/5/2021 9:11:47 PM, Site = , Source = Windows Error Reporting, Message = Fault bucket 1617108784218071861, type 5
Event Name: RADAR_PRE_LEAK_64
Response: Not available
Cab Id: 0

Problem signature:
P1: Vintagestory.exe
P2: 1.14.10.0
P3: 10.0.19041.2.0.0
P4: 
P5: 
P6: 
P7: 
P8: 
P9: 
P10: 

Attached files:
\\?\C:\Users\geoff\AppData\Local\Temp\RDR5B85.tmp\empty.txt
\\?\C:\ProgramData\Microsoft\Windows\WER\Temp\WER5BF3.tmp.WERInternalMetadata.xml
\\?\C:\ProgramData\Microsoft\Windows\WER\Temp\WER5C62.tmp.xml
\\?\C:\ProgramData\Microsoft\Windows\WER\Temp\WER5CEC.tmp.csv
\\?\C:\ProgramData\Microsoft\Windows\WER\Temp\WER5D89.tmp.txt

These files may be available here:


Analysis symbol: 
Rechecking for solution: 0
Report Id: c6aeebad-4568-4d7b-b694-6299e7e3da81
Report Status: 268435456
Hashed bucket: 53ec02d71894ee5b26711fdf167b6335
Cab Guid: 0 }
--------------
{ TimeGenerated = 6/9/2021 5:11:54 PM, Site = , Source = .NET Runtime, Message = Application: Vintagestory.exe
Framework Version: v4.0.30319
Description: The process was terminated due to an unhandled exception.
Exception Info: exception code c0020001, exception address 00007FFCFE5E4B89
Stack:
 }