If you want to clear the program but keep the card's integrity: siemens mmc card - Support
Release the switch and immediately (within 3 seconds) flip it back to . siemens mmc card format tool
For newer controllers, the TIA Portal Engineering Software provides a dedicated tool: Go to for the connected CPU. Expand the Functions folder in the project tree. Select Format memory card and click the Format button. If you want to clear the program but
Standard operating system formatting (FAT32, NTFS) will a Siemens MMC, making it unusable in a PLC environment. A standard PC card reader can often read the data, but attempting to "Format" via Windows Explorer destroys the hidden system image Siemens uses to identify the card to the CPU. Authorized Methods to Format or Reset a Siemens MMC Select Format memory card and click the Format button