If you own the game on , you can right-click RimWorld > Properties > Betas and select version-1.4.3901 from the dropdown to get a complete, verified copy.
It looks like you are referencing a specific archived version of (v1.4.3580). If you are looking for a "piece" in the context of a missing file, a mod, or a specific fix for that version, I can point you in the right direction depending on what you need. RimWorld.v1.4.3580.zip
If the .zip file is missing a "piece" to make it run (like a .dll or the RimWorldWin64.exe ), it’s usually because an antivirus program flagged and quarantined it. If you own the game on , you
If you are playing offline, many modders keep "Legacy" branches of their mods specifically for 1.4. 3. Updating to the Latest 1.4 (or 1.5) If the
Since v1.4.3580 is an older sub-version of the 1.4 "Biotech" era, most mods labeled for should work. However, if you are looking for a specific "piece" of content: Steam Workshop: You can filter by version 1.4.
Here are the most common things people look for with specific RimWorld versions: 1. Missing Executable or Runtime Files