Ensure you have the latest Qualcomm USB Drivers or MTK VCOM Drivers installed on your PC.
Yes, the tool itself is free to download. However, you must purchase credits (approximately £20 / $25 USD) to activate its unlocking functions. The free download alone will not unlock your device . s1 network unlock tool download updated
In many countries, unlocking a phone that is still under contract with a carrier may violate the terms of service. Ensure you have the legal right to unlock your device before proceeding. Ensure you have the latest Qualcomm USB Drivers