Sandcastle issues BHT0001 Warning message

Jun 16, 2010 at 11:56 PM

I have installed Sandcastle on two different machines and I get the same warning message on both of them.

SHFB : warning BHT0001: Unable to get executing project: Unable to obtain internal reference. 
The specified project will be loaded but command line property overrides will be ignored. [c:\xxx\Docs\xxx.shfbproj]

The documentation does not explain what this means or how to resolve it. Can anyone give me some suggestions?



Jun 17, 2010 at 4:21 PM

This is a Sancastle Help File Builder issue.  For such issues, please post over in the SHFB discussion forum (  In this particular case, you are most likely trying to build a SHFB project with MSBuild 4.0 which is not supported yet.  SHFB is build against .NET 3.5 and uses MSBuild 3.5.  As such, use MSBuild 3.5 to build the SHFB project.  MSBuild 4.0 will be supported in the next release.



Jun 17, 2010 at 8:19 PM

Thanks Eric. Yes, we recently updated to VS2010 and  .NET 4.0 so you are probably right. I look forward to the new version.



Mar 6, 2012 at 4:36 AM

I am also getting the same warning message "Warning BHT0001: Unable to get executing project: Unable to obtain internal reference." with MSbuild 4.0.

So i have following questions:

1) Is this a severe warning, which can cause any functionality to stop?

2) When the newer version will get released with MSBuild 4.0 comapatibilty?


Mar 6, 2012 at 4:00 PM

This is a Sandcastle Help File Builder warning.  Download the latest stable release (v1.9.3.0) or the latest beta release (v. from the SHFB project site ( as they are fully compatible with MSBuild 4.0.  Note that you may need to open and resave your SHFB project in the latest release so that it updates the project file settings to use MSBuild 4.0.