Use a utility such as 7-Zip or WinRAR.
If one part of the sequence is missing, the extraction will fail with an "Unexpected end of data" or "Checksum" error. SS-NitSS-008_v.7z.001
Understanding Multi-Part Archives: How to Handle .7z.001 Files Use a utility such as 7-Zip or WinRAR
This post provides a clear tutorial for users who find split archive files and need to know how to reassemble them. SS-NitSS-008_v.7z.001
Encountering a file ending in can be confusing if one is only used to standard zip folders. This format indicates that a large dataset has been split into multiple smaller pieces for easier storage or transfer. What is a Split Archive?
Ensure that every numbered part (e.g., .001 through the final number) is located in the exact same folder on the computer.