Methods and apparatus for isolating the introduction of software defects in a dispersed storage network (DSN) are disclosed. In various embodiments, a search strategy is employed whereby after identifying a test failure in a current version of the memory software code, a sequence of interim versions of the code between the current version of the memory software code and a previous successfully tested version of the code is determined. A first version of the memory software code is selected from the sequence of interim versions (e.g., from the middle of or approximately in the middle of the sequence) and tested. When testing of the first version does not result in a test failure, a second version of the memory software code is tested, the second version selected from a sub-sequence of the sequence of interim versions between the first version of the code and the current version of the code.