Ignacio,

I have seen this before. And this is a tricky one. What is happening is that by default the SQL Job Agent is executing with your proxy account, using light-weight execution without loading the user profile. That's why you see this weird behavior where the execution is working when the user is logged on to the machine. You can verify that I'm correct by doing the following experiment. Run your SSIS package using the "runas" command. There is an option "/noprofile". If you run it with it, you will most probably see the same behavior as what you see now.

Now what you need to do is to find a way and execute your package with complete user profile. If you find information about this, please post it back.

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