Numerical difficulty arises when DAEs are solved with inconsistent initial values of dependent variables. II can cause the solution failures of many popular DAEs solvers. An initialization subroutine, DAEIS (Differential Algebraic Equations Initialization Subroutine), has been developed to handle this issue. In DAEIS, consistent initial values of dependent variables for index-1 DAEs are obtained through solving a set of nonlinear equations based on the initialization settings. To achieve good efficiency and robustness of the initialization computation, a nonlinear equation solver, GNES, has been specially built for DAEIS. The usage of DAEIS is demonstrated through handling inconsistent initializations for combined continuous/discrete simulations.