Borrowing The Sims 2 Disc: Does It Affect Friend's Save?

No. Borrowing the disc has zero effect on your friend's game.

Why Saves Are Completely Separate

• Saves Live on Hard Drive: The Sims 2 writes all neighborhood, lot, and family data to the computer's hard drive (Documents\EA Games\The Sims 2\Neighborhoods). The disc is read-only code/assets.
• No Disc Writing: The game never writes to the DVD-ROM.
• Unique User Folders: Each Windows/macOS user account has its own "The Sims 2" folder. Your saves are invisible to them, and vice versa.

What You Do Need From Them

• Expansion/Stuff Pack Discs: If they own Nightlife, Pets, Seasons... you need those discs to install the content. The base game disc alone only gives base content.
• Serial Keys: Each pack requires its own registration code (on manual/disc sleeve). You cannot install without the key.
• Custom Content: Their downloaded .package files are in their Downloads folder. You must download your own.

Compatibility Check (Modern OS)

Ensure your OS supports it: Windows 10/11 runs it fine (use 4GB Patch + Graphics Rules Maker for modern GPUs). macOS 10.15+ (Catalina) dropped 32-bit support; the Aspyr port won't run without a VM/Wine wrapper.