Published WCF service - crashing MSVCR120.DLL

we have a WCF service hosted through ASP.NET on IIS. Problem is that service is crashing very often.

This is what I can see in my event log (in czech language - i hope thats not problem):

Název chybující aplikace: w3wp.exe, verze: 10.0.15063.0, časové razítko: 0xacce422f
Název chybujícího modulu: MSVCR120.dll, verze: 12.0.40660.0, časové razítko: 0x577e0f1e
Kód výjimky: 0xc0000409
Posun chyby: 0x000a7646
ID chybujícího procesu: 0x3538
Čas spuštění chybující aplikace: 0x01d4549ac44013ca
Cesta k chybující aplikaci: C:\windows\SysWOW64\inetsrv\w3wp.exe
Cesta k chybujícímu modulu: C:\windows\SYSTEM32\MSVCR120.dll
ID zprávy: 1afed30e-94da-4cd6-a500-94341b07b06e
Úplný název chybujícího balíčku:
ID aplikace související s chybujícím balíčkem:(empty)

I searched some solutions so i tried:

• I tried to attach visual studio debugger to process

• I am sure that my app have allowed 32 bit aplications in appPool settings

• I tried to catch crash with Debug Diagnostit tool so I have dump file - I saw some tutorial, there was advicce to perform Memory Analysis script.. So you can see results bellow (unfortunately I don't understand them).

Last note - We are hosting WCF service which is using our internal DLL which are combination of C# wrappers (managed and unamanaged) and also some C++ libraries which are used by C# wrappers.

Memory Pressure Analysis

Machine Name xxxxx
Operating System Unexpected
Number Of Processors 4
Process ID 12616
Process Image C:\Windows\SysWOW64\inetsrv\w3wp.exe
System Up-Time 00:57:22
Process Up-Time 00:03:49

Virtual Memory Summary

Size of largest free VM block 1,99 GBytes
Free memory fragmentation 38,68%
Free Memory 3,25 GBytes (81,22% of Total Memory)
Reserved Memory 446,21 MBytes (10,89% of Total Memory)
Committed Memory 322,96 MBytes (7,88% of Total Memory)
Total Memory 4,00 GBytes
Largest free block at 0x00000000`80010000

Virtual Memory Details

Virtual Allocations  520,95 MBytes
Loaded Modules  235,34 MBytes
Threads  11,00 MBytes
System  0 Bytes
Page Heaps 0 Bytes
Native Heaps 1,88 MBytes

Virtual Allocation Summary

Reserved memory 435,62 MBytes
Committed memory 85,33 MBytes
Mapped memory 75,50 MBytes
Reserved block count 209 blocks
Committed block count 452 blocks
Mapped block count 167 blocks

Loaded Module Summary

Number of Modules 172 Modules
Total reserved memory 260,00 KBytes
Total committed memory 235,09 MBytes

Thread Summary

Number of Threads 40 Thread(s)
Total reserved memory 9,96 MBytes
Total committed memory 1,04 MBytes


Thread ID System ID EntryPoint Reserved Committed
0 12220 0x00000000 220,00 KBytes 36,00 KBytes
1 7592 0x00000000 240,00 KBytes 16,00 KBytes
2 4720 0x00000000 224,00 KBytes 32,00 KBytes
3 11496 0x00000000 240,00 KBytes 16,00 KBytes
4 7856 0x00000000 240,00 KBytes 16,00 KBytes
5 11936 0x00000000 228,00 KBytes 28,00 KBytes
6 5348 0x00000000 240,00 KBytes 16,00 KBytes
7 4344 0x00000000 240,00 KBytes 16,00 KBytes
8 6852 0x00000000 188,00 KBytes 68,00 KBytes
9 13248 0x00000000 240,00 KBytes 16,00 KBytes
10 5636 0x00000000 240,00 KBytes 16,00 KBytes
11 3976 0x00000000 240,00 KBytes 16,00 KBytes
12 4284 0x00000000 240,00 KBytes 16,00 KBytes
13 4992 0x00000000 496,00 KBytes 16,00 KBytes
14 5772 0x00000000 496,00 KBytes 16,00 KBytes
15 10848 0x00000000 496,00 KBytes 16,00 KBytes
16 5124 0x00000000 496,00 KBytes 16,00 KBytes
17 5584 0x00000000 240,00 KBytes 16,00 KBytes
18 848 0x00000000 240,00 KBytes 16,00 KBytes
19 7376 0x00000000 240,00 KBytes 16,00 KBytes
20 9808 0x00000000 4,00 KBytes 252,00 KBytes
21 11808 0x00000000 204,00 KBytes 52,00 KBytes
22 11864 0x00000000 240,00 KBytes 16,00 KBytes
23 2160 0x00000000 240,00 KBytes 16,00 KBytes
24 4904 0x00000000 208,00 KBytes 48,00 KBytes
25 4072 0x00000000 240,00 KBytes 16,00 KBytes
26 7800 0x00000000 228,00 KBytes 28,00 KBytes
27 11820 0x00000000 236,00 KBytes 20,00 KBytes
28 8576 0x00000000 240,00 KBytes 16,00 KBytes
29 9764 0x00000000 240,00 KBytes 16,00 KBytes
30 11452 0x00000000 240,00 KBytes 16,00 KBytes
31 1960 0x00000000 236,00 KBytes 20,00 KBytes
32 3548 0x00000000 240,00 KBytes 16,00 KBytes
33 3948 0x00000000 240,00 KBytes 16,00 KBytes
34 7692 0x00000000 240,00 KBytes 16,00 KBytes
35 2500 0x00000000 240,00 KBytes 16,00 KBytes
36 1676 0x00000000 240,00 KBytes 16,00 KBytes
37 8088 0x00000000 240,00 KBytes 16,00 KBytes
38 4232 0x00000000 240,00 KBytes 16,00 KBytes
39 1608 0x00000000 240,00 KBytes 16,00 KBytes

Heap Summary

Number of heaps 15 Heaps
Total reserved memory 3,46 GBytes
Total committed memory 10,65 GBytes

Top 10 heaps by reserved memory

0x20960000  3,45 GBytes
0x04da0000 6,34 MBytes
0x05340000 0 Bytes
0x05da0000 0 Bytes
0x06220000 0 Bytes
0x05e00000 0 Bytes
0x06560000 0 Bytes
0x06520000 0 Bytes
0x064d0000 0 Bytes
0x066f0000 0 Bytes

Top 10 heaps by committed memory

0x20960000 9,11 GBytes
0x04da0000 1,54 GBytes
0x05340000 0 Bytes
0x05da0000 0 Bytes
0x06220000 0 Bytes
0x05e00000 0 Bytes
0x06560000 0 Bytes
0x06520000 0 Bytes
0x064d0000 0 Bytes
0x066f0000 0 Bytes

Heap Details

Heap 1 - 0x05170000
Heap Name Microsoft VC Runtime Heap (private)
Heap Description This is a private CRT heap used by mscoreei
Reserved memory 0 Bytes
Committed memory 0 Bytes (

Thank you for every advice.