# Engine Error at random point

**URL:** <https://discourse.stonehearth.net/t/engine-error-at-random-point/21716>\
**Category:** Previous Build Reports\
**Created:** [April 25, 2016, 6:44am UTC](https://discourse.stonehearth.net/t/engine-error-at-random-point/21716 "2016-04-25T06:44:40Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![GeyserGod](https://sea2.discourse-cdn.com/flex022/user_avatar/discourse.stonehearth.net/geysergod/32/15662_2.png) [@GeyserGod](https://discourse.stonehearth.net/u/GeyserGod)\
**Post date:** [April 25, 2016, 6:44am UTC](https://discourse.stonehearth.net/t/engine-error-at-random-point/21716/1 "2016-04-25T06:44:40Z")

</div>

**Summary:**  
Just had this pop up after I started building a template building.  
**Steps to reproduce:**  
didn’t happen the first time so don’t think it is actually related to the building project but an item that is being used in the project.  
**Expected Results:**

**Actual Results:**  
Can’t see anything that isn’t where it is supposed to be or that is actually broken just see the error report  
**Notes:**  
This is the second time I have gotten this error and both times I have not notice anything actually wrong but I always have 2-5 things going on at a time so it could be a person crafting, a person building, a person farming, or a person mining but I don’t know which. The first time this happened was on another game in which I maxed the population at 20 before I got the message.  
**Error Message:**  
release-549 (x64)  
…onehearth/components/building/building\_component.lua:586: attempt to index a nil value  
stack traceback:  
radiant/modules/common.lua:223: in function 'report\_traceback’  
radiant/modules/common.lua:234: in function \<radiant/modules/common.lua:228\>  
…onehearth/components/building/building\_component.lua:586: in function ‘\_on\_child\_finished’  
…onehearth/components/building/building\_component.lua:322: in function 'instance’  
radiant/modules/events.lua:206: in function \<radiant/modules/events.lua:200\>  
[C]: in function 'xpcall’  
radiant/modules/common.lua:243: in function 'xpcall’  
radiant/modules/events.lua:200: in function 'trigger’  
radiant/modules/events.lua:241: in function '\_fire\_async\_triggers’  
radiant/modules/events.lua:319: in function '\_update’  
radiant/server.lua:62: in function \<radiant/server.lua:58\>  
**Version Number and Mods in use:**  
a15r549x64  
**System Information:**  
Windows 10 Pro  
Nvidia Geforce GT 730 driver vs. 364.72  
Screen Resoultion 1600x900 60Hz  
24 GB RAM  
Intel i7-3770 CPU 3.4GHz