A dispersed storage network facilitates isolating the introduction of software defects in dispersed storage units. A search strategy is employed whereby after identifying a test failure in a current version of the memory software code, a code version since a previous successfully tested version is identified. An interim version that represents the point at which approximately one half the changes were introduced is then tested. When there is a test failure, the next interim version selected for testing represents the point at which approximately one half the changes were introduced between the first interim version tested and the current version. If no failure, a next interim version is tested that represents the point at which approximately one half the changes were introduced between the previous successfully tested version and the first interim version tested.