On my current project, we’re using SSIS quite extensively for uploading data (text files) from the mainframe to our database. Although the body of the work is mostly finished, I still had to bundle all the work in an easy to run package. Until now, I had always manually run all the different packages that are required for the upload. So last week, I spent some time creating a ‘master’ package that calls all the (child) packages in the correct order. I first edited all my child packages to use parent configuration: this way, I can specify the configuration at the top-level, and all child-packages pick up this setting automatically (and I still can run the packages by themselves if I want). I then created the parent package: it consists of a number of ExecutePackage tasks, which just pass control the configured child package. I thought that all of this could be completed in a few hours, but alas, when I tried to run the parent package, I almost immediately got the following error:

Error: Error 0xC0012050 while loading package file “<SomeChildPackage>.dtsx”. Package failed validation from the ExecutePackage task. The package cannot run. .

I hoped the child package’s output would show more information on what went wrong, but nope, nothing. After some experiments, I found out that I could get things to work by setting the ExecuteOutOfProcess property of the ExecutePackageTask to true. This forces SSIS to create a separate process for each child package to run in. However I noticed that these processes are not cleaned up quickly: several minutes after the parent package had completed, I still saw several dthost.exe process running, each taking a considerable amount of memory. Btw, I half expected this to be the case, as I remembered this post.

So, although I now had a work-around, I still was confused as to why my packages wouldn’t work if I ran them in the same process as their parent. I didn’t want to spend more time on it, so I went to create some other parent packages (for other parts of the project). I tried running one before I had set the ExecuteOutOfProcess property of each child-package, and behold, some (but not all) of the child-packages did run! I compared the properties of the child packages (both of the ExecutePackage task as of the child package itself), and found that the only difference between a working and a non-working child package was that the DelayValidation property of the non-working ones was set to true! Changing it to false solved the problem!

So, the short version of this is: if you get the above error when running a child-package with the ExecutePackage task, make sure that DelayValidation is set to false on the child-package definition (the package itself, not the ExecutePackageTask)!