PyDFix is a tool that helps detect and fix dependency errors that cause the unreproducibility of Python builds. PyDFix takes as input the current build log, the original build log and the source code. PyDFix first identifies dependency errors and possible dependency packages causing these errors using LogErrorAnalyzer. This is followed by iteratively building a patch that makes the build reproducible again by Itera- tiveDependencySolver. The iterative algorithm for building the patch keeps re-running the build with intermediate patches and analyzing the new build logs produced to further identify errors and problematic dependency version specifications. This process continues until the build becomes reproducible, or all patch options have been tested and deemed not useful.