Handling The Sims 4 multi-part archives from fitgirl-repacks.site, particularly in the final stages of a 66-part download, requires ensuring all parts are present in a single folder for correct extraction, with 7-Zip often being more stable. If extraction fails at the end, users should verify they have enough drive space for the uncompressed game and redownload any corrupted or missing files, such as part 66. For more instructions, visit the official fitgirl-repacks.site.