Why do I get the following error when building a setup project?
An error occurred while validating. HRESULT = '80004005'
Both of the reasons I found are already in other answers, but they are in separate answers and not fully explained. So, hopefully this will combine the possibilities and give good means of debugging each. :)
Common Reason
My problem was not a dependency error. However, that does seem to be the common reason. So, basically, you need to check your MSI file and make sure that all dependencies are still valid. Probably the best blog response on how you can easily resolve this if it is a dependency issue is An error occurred while validating. HRESULT = '80004005'.
Extract from blog:
Follow steps below to troubleshoot.
- If you have multiple project outputs in your solution, identify the project that is giving the problem. You can do that by removing one project at a time from the Setup Project(S) until error goes away.
Once project is identified, identify the reference that could be giving the problem.
- Check if the project(A) is referencing to a project that has been removed from solution. - Remove such references if any.
- Check if the Project(A) is referencing to a project that was moved to a diffenrent physical location after it was added as a reference. - Remove and add such references.
Rebuild setup project after fixing the reference accordingly to see if error goes away.
Alternative Reason
My problem had to do with Visual Studio versioning, however. So, if your dependencies are valid and you still are getting this problem, then you resolve this if it is a problem with VS2010 .
Basically, if you run MSBuild and see this warning:
Project file contains ToolsVersion="4.0", which is not supported by this version of MSBuild. Treating the project as if it had ToolsVersion="3.5"
Then the problem is Visual Studio versioning. This means that one project was opened or created in Visual Studio 2010 and then saved or added to an existing 3.5 solution. I simply searched all files in my project for ToolsVersion="4.0" and found the offending .csproj file, opened it in a text editor and manually changed the 4.0 to a 3.5.