Right-click on the .001 file specifically.
Ensure you have every numbered file in the sequence (Reb1MF.7z.001, Reb1MF.7z.002, etc.) saved in the same directory. Reb1MF.7z.001
If you did not expect to receive this file or downloaded it from an unverified source, exercise caution. Split archives are sometimes used to bypass email or browser file-size limits, but they can also be used to hide malicious executables from basic scanners. Right-click on the
Large textures or "re-baked" (REB) game files. Reb1MF.7z.001
The file is a split archive file, specifically the first part of a multi-volume compressed archive created using 7-Zip.