Use the function to save a backup image of a working MMC.
If you do not own an expensive Siemens USB Prommer, you can format and clear the MMC directly inside the PLC CPU using the mode selector switch. When to use this:
There are two primary ways to format or clear a Siemens MMC without damaging its internal structure:
If someone accidentally formatted the card via Windows, the internal architecture is gone. TIA Portal will no longer recognize it. You must use a third-party image restoration tool to burn an exact .wld or .img backup file back onto the card. Popular Tool Options: siemens mmc card format tool
Within the next 3 seconds, release the switch back to STOP, and immediately turn it back to again.
Are you a Siemens automation user who has experienced an MMC formatting disaster? Share your recovery story and tips with the community to help fellow engineers avoid the same costly mistakes.
The Siemens MMC card format tool is a software utility designed specifically for formatting MMC cards used in Siemens devices. This tool is developed by Siemens to ensure that MMC cards are properly formatted and functioning correctly. The tool is user-friendly and can be easily downloaded from the Siemens website. Use the function to save a backup image of a working MMC
💡 If the tool cannot read the card at all, try a different card reader. Some modern generic USB readers struggle with the proprietary format of Siemens industrial cards.
Handling these cards requires a shift in mindset from "storage media" to "system firmware." By using the official tools—Simatic Manager or SAT—you ensure the file system remains compatible with the S7 platform.
Sometimes, the card is so corrupted that Simatic Manager or SAT won't even recognize it, or the format button is grayed out. This is the most common panic scenario for engineers. TIA Portal will no longer recognize it
Formatting should be a last resort. Here are best practices to keep your MMCs healthy:
If you are a seasoned engineer working on legacy systems (S7-300/400), you are likely still using Step 7 v5.x (Simatic Manager). Formatting a card here is integrated directly into the programming environment. This is the "MMC Card Format Tool" most people refer to.
