You must have every single segment (part1, part2, etc.) in the same folder. If one is missing or corrupted, the extraction will fail.
While the filename might look like a string of placeholder characters, for those in the [Cybersecurity / Archival / Gaming] community, it represents a massive undertaking in data preservation and distribution. Why Multi-Part RAR Files?
A .part1.rar file alone is . You cannot open it, play it, or install it without the subsequent parts.