I'm commenting here because I found this thread while searching for a similar problem:
http://forum.piriform.com/?showtopic=37716
The aforementioned thread was quickly shut down with cries of 'we don't do malware' but--in my case at least--the files are from a legitimate source. The .NET assembly binder. I've posted one of the files below.
When .NET logging is configured every .NET application will create one of these 2k-3k files every time any .NET application is launched. System applications tend to dump the files in the folder(s) mentioned in that original thread:
c:\windows\system32\config\systemprofile\appdata\local\Microsoft\windows\Temporary Internet FIles\Content.IE5
c:\windows\syswow64\config\systemprofile\appdata\local\Microsoft\windows\Temporary Internet FIles\Content.IE5
Given that these can get quickly out of hand (My C: drive has over 30G consumed by about 7.5 million of the little buggers)
It would be nice if CCleaner had the ability to clean them up along with everything else.
*** Assembly Binder Log Entry (12/30/2013 @ 10:06:23 AM) ***
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\mscorsvw.exe
— A detailed error log follows.
=== Pre-bind state information ===
LOG: DisplayName = System.Design, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
(Fully-specified)
LOG: Appbase = file:///C:/Windows/Microsoft.NET/Framework/v4.0.30319/
LOG: Initial PrivatePath = NULL
LOG: Dynamic Base = NULL
LOG: Cache Base = NULL
LOG: AppName = mscorsvw.exe
Calling assembly : (Unknown).
===
LOG: This bind starts in default load context.
LOG: Download of application configuration file was attempted from file:///C:/Windows/Microsoft.NET/Framework/v4.0.30319/mscorsvw.exe.config.
LOG: Configuration file C:\Windows\Microsoft.NET\Framework\v4.0.30319\mscorsvw.exe.config does not exist.
LOG: No application configuration file found.
LOG: Using host configuration file:
LOG: Using machine configuration file from C:\Windows\Microsoft.NET\Framework\v4.0.30319\config\machine.config.
LOG: Post-policy reference: System.Design, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
LOG: Found assembly by looking in the GAC.
LOG: Binding succeeds. Returns assembly from C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.Design\v4.0_4.0.0.0__b03f5f7f11d50a3a\System.Design.dll.
LOG: Assembly is loaded in default load context.