Recently a package of mine with a good running history suddenly started throwing errors. This package had been scheduled and running just fine for over a month – no changes to the code had been made. The error is consistently thus:

The script threw an exception: A deadlock was detected while trying to lock variables MyVariables for read access and variables MyVariables for read/write access. A lock cannot be acquired after 16 attempts. The locks timed out.Task MyTask failed.

Luckily, I am not the only one who has run into this issue, and it has now inspired a new practice for me in designing Script Tasks inside my SSIS packages. Previously in one of my posts, I had shown the following screenshot and described the standard method for using read only and read/write variables in a script task:

For many situations, this will probably work out just fine. However, my variable locking issue has evolved from my use of a Foreach container that holds my Script Task. There are other examples in my package store not involving a Foreach that also throw this error, however all of my packages that consistently throw this error all have in common the use of a Script Task inside a repeated process – for some reason, SSIS is not properly releasing the variables between runs of the step.

Daniel Read has written a detailed method on how to work around this; you may find his post here: http://www.developerdotstar.com/community/node/512/