17. A computing device communicationally coupled to a storage device and a software restriction policy store, the computing device comprising a processing unit performing steps comprising: obtaining an excluded listing for which software restriction policy rules preventing execution of applicable executable files are to be generated; generating, in accordance with user-specified preferred types of software restriction policy rules that are preferred by the user, a software restriction policy rule for each entry in a specified metadata source on the storage device, so long as the generated software restriction policy rule is not duplicative previously generated software restriction policy rule, the generated software restriction policy rule being an allow software restriction policy rule, allowing execution of applicable executable files, if an entry for which the allow software restriction policy rule was generated was absent from the excluded list, and the generated software restriction policy rule being a deny software restriction policy rule, preventing execution of applicable executable files, if an entry for which the deny software restriction policy rule was generated was present on the excluded list; generating, instead of the deny software restriction policy rule, an exception to an existing allow software restriction policy rule if the existing allow software restriction policy rule is applicable to all executable files to which the deny software restriction policy rule would have applied; and storing the generated software restriction policy rules in the software restriction policy store.
17. A computing device communicationally coupled to a storage device and a software restriction policy store, the computing device comprising a processing unit performing steps comprising: obtaining an excluded listing for which software restriction policy rules preventing execution of applicable executable files are to be generated; generating, in accordance with user-specified preferred types of software restriction policy rules that are preferred by the user, a software restriction policy rule for each entry in a specified metadata source on the storage device, so long as the generated software restriction policy rule is not duplicative previously generated software restriction policy rule, the generated software restriction policy rule being an allow software restriction policy rule, allowing execution of applicable executable files, if an entry for which the allow software restriction policy rule was generated was absent from the excluded list, and the generated software restriction policy rule being a deny software restriction policy rule, preventing execution of applicable executable files, if an entry for which the deny software restriction policy rule was generated was present on the excluded list; generating, instead of the deny software restriction policy rule, an exception to an existing allow software restriction policy rule if the existing allow software restriction policy rule is applicable to all executable files to which the deny software restriction policy rule would have applied; and storing the generated software restriction policy rules in the software restriction policy store. 18. The computing device of claim 17 , wherein the user-specified preferred types of software restriction policy rules that are preferred by the user are at least one of: a publisher-based rule, a hash-based rule, and a path-based rule.