How to enable assembly bind failure logging (Fusion) in .NET

Question

How do I enable assembly bind failure logging (Fusion) in .NET?

Answer 1

Add the following values to

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Fusion
Add:
DWORD ForceLog set value to 1
DWORD LogFailures set value to 1
DWORD LogResourceBinds set value to 1
DWORD EnableLog set value to 1
String LogPath set value to folder for logs (e.g. C:\FusionLog\)

Make sure you include the backslash after the folder name and that the Folder exists.

You need to restart the program that you're running to force it to read those registry settings.

By the way, don't forget to turn off fusion logging when not needed.

Answer 2

Set the following registry value:

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Fusion!EnableLog] (DWORD) to 1

To disable, set to 0 or delete the value.

[edit ]:Save the following text to a file, e.g FusionEnableLog.reg, in Windows Registry Editor Format:

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Fusion]
"EnableLog"=dword:00000001

Then run the file from windows explorer and ignore the warning about possible damage.

Answer 3

You can run this Powershell script as administrator to enable FL:

Set-ItemProperty -Path HKLM:\Software\Microsoft\Fusion -Name ForceLog         -Value 1               -Type DWord
Set-ItemProperty -Path HKLM:\Software\Microsoft\Fusion -Name LogFailures      -Value 1               -Type DWord
Set-ItemProperty -Path HKLM:\Software\Microsoft\Fusion -Name LogResourceBinds -Value 1               -Type DWord
Set-ItemProperty -Path HKLM:\Software\Microsoft\Fusion -Name LogPath          -Value 'C:\FusionLog\' -Type String
mkdir C:\FusionLog -Force

and this one to disable:

Remove-ItemProperty -Path HKLM:\Software\Microsoft\Fusion -Name ForceLog
Remove-ItemProperty -Path HKLM:\Software\Microsoft\Fusion -Name LogFailures
Remove-ItemProperty -Path HKLM:\Software\Microsoft\Fusion -Name LogResourceBinds
Remove-ItemProperty -Path HKLM:\Software\Microsoft\Fusion -Name LogPath

Answer 4

Instead of using a ugly log file, you can also activate Fusion log via ETW/xperf by turning on the DotnetRuntime Private provider (Microsoft-Windows-DotNETRuntimePrivate) with GUID 763FD754-7086-4DFE-95EB-C01A46FAF4CA and the FusionKeyword keyword (0x4) on.

@echo off
echo Press a key when ready to start...
pause
echo .
echo ...Capturing...
echo .

"C:\Program Files (x86)\Windows Kits\8.1\Windows Performance Toolkit\xperf.exe" -on PROC_THREAD+LOADER+PROFILE -stackwalk Profile -buffersize 1024 -MaxFile 2048 -FileMode Circular -f Kernel.etl
"C:\Program Files (x86)\Windows Kits\8.1\Windows Performance Toolkit\xperf.exe" -start ClrSession -on Microsoft-Windows-DotNETRuntime:0x8118:0x5:'stack'+763FD754-7086-4DFE-95EB-C01A46FAF4CA:0x4:0x5 -f clr.etl -buffersize 1024

echo Press a key when you want to stop...
pause
pause
echo .
echo ...Stopping...
echo .

"C:\Program Files (x86)\Windows Kits\8.1\Windows Performance Toolkit\xperf.exe" -start ClrRundownSession -on Microsoft-Windows-DotNETRuntime:0x8118:0x5:'stack'+Microsoft-Windows-DotNETRuntimeRundown:0x118:0x5:'stack' -f clr_DCend.etl -buffersize 1024 

timeout /t 15

set XPERF_CreateNGenPdbs=1

"C:\Program Files (x86)\Windows Kits\8.1\Windows Performance Toolkit\xperf.exe" -stop ClrSession ClrRundownSession 
"C:\Program Files (x86)\Windows Kits\8.1\Windows Performance Toolkit\xperf.exe" -stop
"C:\Program Files (x86)\Windows Kits\8.1\Windows Performance Toolkit\xperf.exe" -merge kernel.etl clr.etl clr_DCend.etl Result.etl -compress
del kernel.etl
del clr.etl
del clr_DCend.etl

When you now open the ETL file in PerfView and look under the Events table, you can find the Fusion data:

Answer 5

For those who are a bit lazy, I recommend running this as a bat file for when ever you want to enable it:

reg add "HKLM\Software\Microsoft\Fusion" /v EnableLog /t REG_DWORD /d 1 /f
reg add "HKLM\Software\Microsoft\Fusion" /v ForceLog /t REG_DWORD /d 1 /f
reg add "HKLM\Software\Microsoft\Fusion" /v LogFailures /t REG_DWORD /d 1 /f
reg add "HKLM\Software\Microsoft\Fusion" /v LogResourceBinds /t REG_DWORD /d 1 /f
reg add "HKLM\Software\Microsoft\Fusion" /v LogPath /t REG_SZ /d C:\FusionLog\

if not exist "C:\FusionLog\" mkdir C:\FusionLog

Answer 6

I usually use the Fusion Log Viewer (Fuslogvw.exe from a Visual Studio command prompt or Fusion Log Viewer from the start menu) - my standard setup is:

• Open Fusion Log Viewer as administrator
• Click settings
• Check the Enable custom log path checkbox
• Enter the location you want logs to get written to, for example, c:\FusionLogs (Important: make sure that you have actually created this folder in the file system.)
• Make sure that the right level of logging is on (I sometimes just select Log all binds to disk just to make sure things are working right)
• Click OK
• Set the log location option to Custom

Remember to turn of logging off once you're done!

(I just posted this on a similar question - I think it's relevant here too.)