Many, if not all, "open source" IDM resetter RAR files found online are likely not truly open source. Open source implies the source code is public, verifiable, and editable, which is rarely true for tools designed to bypass licensing.
Disclaimer: Downloading cracked software or tools designed to bypass licensing is risky and may violate legal agreements. Download [opensource] IDM trial reset rar
IDM regularly updates to patch these reset methods. Many, if not all, "open source" IDM resetter