Command-line environment a-la WinDbg for executing SOS commands without having SOS available.
Latest commit e9b4005 Sep 30, 2016 @goldshtn Reload symbols in native target and display diagnostic information
When --diag is requested, pass `!sym noisy` to the native DbgEng target so that we get detailed symbol diagnostic information.


This project provides a command-line environment a-la WinDbg for executing SOS commands without having SOS available. It is based on the ClrMD library that is essentially a managed replacement for SOS.

Build status: Build status

You should use this project when you don't have SOS available, or when you want a quick alternative to firing up WinDbg and locating SOS. One such situation is when debugging dumps from Windows Phone devices; Microsoft does not make the Windows Phone CoreCLR SOS publicly available at present. What's more, some msos commands already offer more information than their SOS counterparts. Especially cool is the !hq command, which compiles an arbitrary dynamic query over heap objects and classes.


Currently, msos depends on a fork of the Microsoft CLRMD library. You will need to configure your NuGet package feed to include the following feed: before restoring NuGet packages.

You can also find the binary artifacts from any build on AppVeyor. Navigate to the x86 or x64 build, and then click Artifacts to download the binary archive.

Basic Usage

To use msos, compile the project and run it from the command line with a dump file or a live target:

msos -z myapp.dmp
msos --pn myprocess.exe

Type help to get a list of currently supported commands. Note that some options might currently be unsupported, and are marked as such by the built-in help.

Head on to the Wiki to get started and to review the full documentation.


0> !dumpheap --type String$ --stat
MT                   Count      TotalSize  Class Name
000000006e21565c     14751      1046116    System.String
Total 14751 objects
Elapsed: 121ms

1> !hq tabular from o in ObjectsOfType("System.IO.StreamReader") select new { SR = o.GetValue(), CP = o.encoding.m_codePage }
SR                                                  CP
33307512                                            437
Rows: 1
Time: 604 ms, Memory start: 124.930kb, Memory end: 157.840kb, Memory delta: +32.910kb

1> !hq tabular Class("System.String").__Fields
Name                                                Type
m_stringLength                                      System.Int32
m_firstChar                                         System.Char
Rows: 2
Time: 530 ms, Memory start: 124.145kb, Memory end: 157.254kb, Memory delta: +33.109kb

1> !hq tabular from s in ObjectsOfType("System.String") where s.__Size > 100 select new { Str = (string)s, Size = s.__Size }
Str                                                 Size
...C:\Temp\VSDebugging\bin\Debug\VSDebugging.exe.C  118
C:\Temp\VSDebugging\bin\Debug\VSDebugging.exe       104
C:\Windows\Microsoft.NET\Framework\v4.0.30319\      106
...C:\Windows\Microsoft.NET\Framework\v4.0.30319\c  148
...System\CurrentControlSet\Control\Nls\RegionMapp  114
Rows: 5
Time: 697 ms, Memory start: 125.262kb, Memory end: 160.242kb, Memory delta: +34.980kb

0> !ThreadPool
Total threads:   24
Running threads: 1
Idle threads:    10
Max threads:     1023
Min threads:     2
CPU utilization: 48% (estimated)
Elapsed: 2ms

0> !do 00000000017eddbc
Name:     System.Threading.TimerQueueTimer
MT:       000000006e209bc8
Size:     52(0x34) bytes
Assembly: C:\windows\system32\
Value:    1847630792
Offset   Type                 VT  Attr       Value                Name
0        ....TimerQueueTimer  0   instance   00000000017edc18     m_next
4        ....TimerQueueTimer  0   instance   0000000001810ec4     m_prev
8  0   instance   000000000155cef0     m_timerCallback
c        System.Object        0   instance   00000000017edd70     m_state
10       ...ExecutionContext  0   instance   000000000141f57c     m_executionContext
14       ...ading.WaitHandle  0   instance   0000000000000000     m_notifyWhenNoCallbacksRunning
18       System.Int32         1   instance   000000000202871b     m_startTicks
1c       System.UInt32        1   instance   00000000000003e8     m_dueTime
20       System.UInt32        1   instance   00000000ffffffff     m_period
24       System.Int32         1   instance   0000000000000000     m_callbacksRunning
28       System.Boolean       1   instance   False                m_canceled
17c      ....ContextCallback  0   instance   static               s_callCallbackInContext
   >> Domain:Value  000000000120e850:NotInit <<
Elapsed: 24ms

0> !gcroot 0000000001581a84
000000000101131C -> 00000000015801C4 RefCount handle
        -> 00000000015801C4 System.Runtime.InteropServices.WindowsRuntime.CustomPropertyImpl
        -> 0000000001577948 System.Reflection.RuntimePropertyInfo
        -> 000000000156A18C System.RuntimeType+RuntimeTypeCache
        -> 0000000001574E0C System.RuntimeType+RuntimeTypeCache+MemberInfoCache<System.Reflection.RuntimePropertyInfo>
        -> 0000000001581A70 System.Reflection.CerHashtable+Table<System.String,System.Reflection.RuntimePropertyInfo[]>
        -> 0000000001581A84 System.String[]

Elapsed: 635ms