Our SSIS pacakges a structured as one Control package and many child packages (about 30) that are invoked from the control package. The child packages are invoked with Execute Package Task. There is one Execute Package Task per child package. Each Execute Package Task uses File Connection Manager to specify path to the child package dtsx file. There is one File Connection Manager per child package. Each File Connection Manager has an expression defined for ConnectionString property. This expression looks like this: @[Template::FolderPackages]+"MyPackage.dtsx", the file name is different for each package. The variable (FolderPackages) is specified in the SSIS package configuration file.

The error that is generated during run time is "Error 0x80070002 while loading package file "MyPackage.dtsx". The system cannot find the file specified." The package that fails is different from run to run and sometimes no packages fail at all. This is when run on exactly the same environment/data etc.

I ran FileMon during this error and found out that when the error happens SSIS tries to read the dtsx file from a wrong place, namely from system32. I checked that this is identical to what would happen if @[Template::FolderPackages] variable were empty, but because the very same variable is used for every child package and works for some but doesn't work sometimes for others, I have no expalnation to this fact.

Anything obvious, or time to raise a support call with Microsoft?