Distinguish the places a save can live
A physical Sega CD system and a modern cartridge that recreates CD hardware do not necessarily share the same storage. Record whether the game is using the physical unit's internal backup RAM, a compatible backup cartridge, or files on a modern cartridge's memory card. The original Sega CD BIOS documentation includes a dedicated backup RAM reference; use it when building a utility or interpreting a storage error.
On a physical system, inspect the BIOS memory manager without choosing format or delete. Photograph the listed game entries and free-space display. A format prompt is not a backup operation. If a unit has been stored for years and contains irreplaceable progress, preserve that data before soldering on the board or replacing the retention component. A fresh retention component cannot recover data that was already lost.
Create a preservation record
- List each game's name, regional edition, visible save slots and last verified progress.
- Note whether the game writes directly to cartridge storage or needs the BIOS manager to copy files.
- Copy a test save using a documented, compatible method before trusting it with the only copy of valuable progress.
- Export the resulting backup to two separate computer locations and retain the original unmodified file.
- Restore to spare storage or a controlled test environment and confirm that the intended game loads it.
The existing Genesis game and save backup guide is a useful companion. A screenshot of a save list establishes that entries existed, but does not establish that a computer backup can restore them. A successful restore test should include actual in-game progress and settings, not just the appearance of a filename.
Modern CD cores need a separate plan
The MegaSD manual describes per-game CD backup RAM and cartridge RAM stored on microSD. Preserve that setting and the associated files together. Changing between shared and per-game storage can make a previously created save appear absent even though a different file is now being selected. Record the cartridge firmware and active setting alongside the archive.
The Mega EverDrive Pro manual distinguishes the attached physical CD mode from its internal CD core and documents RAM Cart support. Check your exact cartridge version and firmware before following an old save-transfer tutorial. Copy the entire relevant save directory initially; after understanding its contents, maintain smaller named archives. Close the session using the cartridge's documented save procedure and remove its card only when safe.
Investigate retention without erasing evidence
If a new save disappears after a normal shutdown, first verify that it was actually committed in the game and that the expected storage target remains selected. Repeat with a disposable test save and record the length of time the unit was unpowered. Then consult the exact board documentation for its retention circuit. Do not substitute a generic coin cell into a charging circuit or assume all Sega CD boards use the same part. A battery repair and a FRAM conversion are different changes with different compatibility requirements. Keep the last known good backup separate from subsequent failed tests.