Rob Kraft's Software Development Blog

Software Development Insights

Did your .Net Build Server Run out of Disk Space? Perhaps it was Fusion Log Viewer.

Posted by robkraft on June 26, 2016

A few months ago our nightly build failed because the build machine was out of disk space.  We cleaned up the usual temp files and got it running again, but decided to dig deeper to find things filling up the hard drive.

We discovered we had a folder with millions (literally millions) of small .htm files.  The folder was C:\windows\syswow64\config\systemprofile\appdata\local\content.ie5 and we learned that the source of these files was Fusion Log Viewer from this post by Rich Beales:

I am just blogging about it here so that I can find this post in the future if it happens to me again, and also to elaborate on some details.

The HTML files were small and the content of every one of them was something like this:

<meta http-equiv=”Content-Type” content=”charset=unicode-1-1-utf-8″><!– saved from url=(0015)assemblybinder: –><html><pre>
*** Assembly Binder Log Entry  (2/1/2016 @ 12:00:34 PM) ***

The operation was successful.
Bind result: hr = 0x0. The operation completed successfully.

Assembly manager loaded from:  C:\Windows\Microsoft.NET\Framework\v4.0.30319\clr.dll
Running under executable  C:\WINDOWS\Microsoft.NET\Framework\v4.0.30319\aspnet_compiler.exe
— A detailed error log follows.

=== Pre-bind state information ===
LOG: DisplayName = System.Configuration, Version=, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
LOG: Appbase = file:///C:/Build/ourapp.Internal/
LOG: Initial PrivatePath = C:\Build\ourapp.Internal\bin
LOG: Dynamic Base = C:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files\ourapp.internal\085749fe
LOG: Cache Base = C:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files\ourapp.internal\085749fe
LOG: AppName = f1c160c1
Calling assembly : (Unknown).
LOG: This bind starts in default load context.
LOG: Using application configuration file: C:\Build\ourapp.Internal\web.config
LOG: Using host configuration file:
LOG: Using machine configuration file from C:\Windows\Microsoft.NET\Framework\v4.0.30319\config\machine.config.
LOG: Binding succeeds. Returns assembly from C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.Configuration\v4.0_4.0.0.0__b03f5f7f11d50a3a\System.Configuration.dll.
LOG: Assembly is loaded in default load context.


The really odd thing for our team is that none of us know what Fusion Logger is about, or that it existed, or how it could have been turned on.  We are suspicious that a .Net or Visual Studio update may have turned it on.  Regardless, to shut it off we tracked down the FusLogVw.exe and changed it from “Log all bind to disk” to “Log disabled”.


Final note, when you decide to delete the files, do so by deleting the whole directory (rd foldername /S), otherwise it make take you days to delete the all.


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