When Windows prompts: "You need to format the disk before you can use it", do not click Format! In most cases, your raw data is still completely intact—only the Master Boot Record (MBR) or file allocation table has been damaged.
1. Assign a New Drive Letter
Sometimes Windows fails to mount a removable volume due to a drive letter collision. Open Disk Management (diskmgmt.msc), right-click the removable drive, select Change Drive Letter and Paths, and assign an unused letter (like X: or Z:).
2. Run CHKDSK to Repair File System Structures
Open Command Prompt as Administrator and run:
chkdsk X: /f /r
(Replace X: with your actual memory card drive letter.) This command scans for bad sectors, recovers readable data, and restores damaged directory records.