Right-click on Setup.exe and select "Run as Administrator".
This is the primary use case. The tool can calculate unlock codes or perform a direct unlock for Mi-Fi devices that are locked to a specific carrier (e.g., locked to AT&T, T-Mobile, or Vodafone). This allows the user to use a SIM card from any compatible carrier.
For users who have forgotten administrator passwords on devices like the Huawei E303 or E355, Mifi Tool 1.0.0.3 includes a brute-force reset module for user-level locks.