Help with error message

I am a Grade 6 Teacher trying to figure Arduinos out. My student programmed a pretty cool code (which I have no idea what it does) but we keep getting an error message. Any help is appreciated.

Arduino: 1.6.9 (Mac OS X), Board: "Arduino/Genuino Uno"

failed MSpanList_Insert 0x30c000 0x3f3efa7344c7 0x0
fatal error: MSpanList_Insert

runtime stack:
/usr/local/go/src/runtime/panic.go:491 +0xad fp=0x7ffeefbff4e0 sp=0x7ffeefbff4b0
runtime.MSpanList_Insert(0x2ca128, 0x30c000)
/usr/local/go/src/runtime/mheap.c:692 +0x8f fp=0x7ffeefbff508 sp=0x7ffeefbff4e0
MHeap_FreeSpanLocked(0x2c6d20, 0x30c000, 0x100)
/usr/local/go/src/runtime/mheap.c:583 +0x163 fp=0x7ffeefbff548 sp=0x7ffeefbff508
MHeap_Grow(0x2c6d20, 0x8, 0x0)
/usr/local/go/src/runtime/mheap.c:420 +0x1a8 fp=0x7ffeefbff588 sp=0x7ffeefbff548
MHeap_AllocSpanLocked(0x2c6d20, 0x1, 0x0)
/usr/local/go/src/runtime/mheap.c:298 +0x365 fp=0x7ffeefbff5c8 sp=0x7ffeefbff588
mheap_alloc(0x2c6d20, 0x1, 0x12, 0x0)
/usr/local/go/src/runtime/mheap.c:190 +0x121 fp=0x7ffeefbff5f0 sp=0x7ffeefbff5c8
runtime.MHeap_Alloc(0x2c6d20, 0x1, 0x10000000012, 0xf989)
/usr/local/go/src/runtime/mheap.c:240 +0x66 fp=0x7ffeefbff628 sp=0x7ffeefbff5f0
MCentral_Grow(0x2cea98, 0x0)
/usr/local/go/src/runtime/mcentral.c:197 +0x8b fp=0x7ffeefbff690 sp=0x7ffeefbff628
runtime.MCentral_CacheSpan(0x2cea98, 0x0)
/usr/local/go/src/runtime/mcentral.c:85 +0x167 fp=0x7ffeefbff6c8 sp=0x7ffeefbff690
runtime.MCache_Refill(0x308000, 0x12, 0x0)
/usr/local/go/src/runtime/mcache.c:90 +0xa0 fp=0x7ffeefbff6f0 sp=0x7ffeefbff6c8
/usr/local/go/src/runtime/malloc.c:368 +0x57 fp=0x7ffeefbff710 sp=0x7ffeefbff6f0
/usr/local/go/src/runtime/asm_amd64.s:273 +0x9a fp=0x7ffeefbff718 sp=0x7ffeefbff710
runtime.mallocgc(0x120, 0x1bde40, 0x0, 0x0)
/usr/local/go/src/runtime/malloc.go:178 +0x849 fp=0x7ffeefbff7c8 sp=0x7ffeefbff718
runtime.newobject(0x1bde40, 0x308000)
/usr/local/go/src/runtime/malloc.go:353 +0x49 fp=0x7ffeefbff7f0 sp=0x7ffeefbff7c8
/usr/local/go/src/runtime/proc.go:233 +0x2a fp=0x7ffeefbff808 sp=0x7ffeefbff7f0
/usr/local/go/src/runtime/proc.c:925 +0x1f fp=0x7ffeefbff818 sp=0x7ffeefbff808
runtime.malg(0x8000, 0x2b9700)
/usr/local/go/src/runtime/proc.c:2106 +0x1f fp=0x7ffeefbff848 sp=0x7ffeefbff818
/usr/local/go/src/runtime/os_darwin.c:137 +0x27 fp=0x7ffeefbff860 sp=0x7ffeefbff848
/usr/local/go/src/runtime/proc.c:201 +0xc9 fp=0x7ffeefbff888 sp=0x7ffeefbff860
/usr/local/go/src/runtime/proc.c:138 +0x55 fp=0x7ffeefbff8b0 sp=0x7ffeefbff888
runtime.rt0_go(0x7ffeefbff8e8, 0x14, 0x7ffeefbff8e8, 0x0, 0x0, 0x14, 0x7ffeefbffa88, 0x7ffeefbffac0, 0x7ffeefbffacc, 0x7ffeefbffadc, ...)
/usr/local/go/src/runtime/asm_amd64.s:95 +0x116 fp=0x7ffeefbff8b8 sp=0x7ffeefbff8b0
arduino-builder returned 2

Error compiling for board Arduino/Genuino Uno.

This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.

Can you use reply->preview to post the program.

My student programmed a pretty cool code (which I have no idea what it does) but we keep getting an error message

How do you know that it is cool if

(a) you don't know what it does
(b) it does not compile, upload and run

As the error is
MSpanList_Insertthen a wild guess would be that an insert of data into an array has strayed outside the bounds of the array but until we see the actual code (in code tags please) then we are working in the dark.

@MRSoClassroom, your error message suggests to me a problem with the Arduino IDE rather than with the Arduino program.

I am not familar with Macs but I have seen cases where the Arduino IDE choked on an Arduino code error probably due to a missing (or an extra) " so that it could not find the end of a piece of text.

Can you upload the Blink example program?

If you can't upload the Blink program I suggest you {A} shut down and restart the PC and if that does not solve the problem {B} delete and re-install the Arduino IDE.


You are using an outdated version of the Arduino IDE. If you update to Arduino IDE 1.8.5, which can be downloaded here:

then the problem will be solved.

More info: