Cheaply manufactured SD2Vita adapters are notorious for high failure rates or physical misalignment.

By following these steps, most users can bypass the C1-2755-9 error and successfully expand their Vita’s library.

If you purchased an unusually cheap high-capacity card (e.g., a 512GB card for $10), it might be a fake that reports a higher capacity than it actually has.

If the Vita cannot format the card, you may need to "blank" it first on a computer to clear conflicting partition tables.