Older CD/DVD versions of SimCity 4 often fail to run on Windows 10/11 due to discontinued support for SafeDisc DRM. Pirated versions often bypass this with "No-CD" cracks, which themselves can be flagged as security threats by antivirus software. Recommended Safe Alternatives

A massive, community-led update that fixes the game's broken traffic pathfinding.

: Generally considered the most stable version for modern systems when used with the right launch options.

The number "(25621)" may refer to a specific internal build or an arbitrary release tag. It is worth noting that certain official digital versions (specifically from the EA App/Origin) are known to be outdated "unpatchable" versions with different checksums compared to the fully updated Steam or GOG releases. Archive & Installation Issues