Your CompactFlash card is been disappeared and no longer been detected or wants to be formatted suddenly, even though seconds ago the card is still working properly?
Be sure the controller of your card is physical damaged, no software can help. The only way to get the data/photos back, unsolder the memory chip, directly dump their raw data with a programmable chip reader and convert it to readable data. Their are only some specialists on earth, they are able to do this complicated procedure.
See also: Reasons for data loss, when can data/photos be saved

Formatting is required? The controller of the memory card is not in the position to inform the PC operating system about the characteristics of the memory card. Therefor the PC assumes, the memory card is not formatted and requests formatting. One could now think, the memory card problems are solved by formatting, unfortunately that does not work due to the damaged controller. Try it out, the PC will communicate, that a formatting is not possible. Finally this is then also a clear proof that any kind of software, also special formatting or rescue software!!, no more can access to the memory card.

This article is licensed under the gnu free documentation license. It uses material from the wikipedia article CompactFlash The authors of that article are listet here.

CompactFlash (CF) is a mass storage device format used in portable electronic devices. For storage, CompactFlash typically uses flash memory in a standardized enclosure. The format was first specified and produced by SanDisk in 1994.[1] The physical format is now used for a variety of devices. CompactFlash became a popular storage medium for digital cameras. In recent years it has been widely replaced by smaller cards on the consumer end, but it is still a preferred format for D-SLR cameras, for its superior capacity and reliability.
Description: There are two main subdivisions of CF cards, Type I (3.3 mm thick) and the thicker Type II (CF2) cards (5 mm thick). The CF Type II slot is used by Microdrives and some other devices. There are four main speeds of cards including the original CF, CF High Speed (using CF+/CF2.0), a faster CF 3.0 standard and a yet faster CF 4.0 standard that is being adopted as of 2007. The thickness of the CF card type is dictated by the preceding PC Card standard which was used for data storage in previous years. CompactFlash was originally built around Intel's NOR-based flash memory, but it has switched over to NAND.[2] CF is among the oldest and most successful formats, and has held to a niche in the professional camera market especially well. It has benefited from having both a better cost to memory-size ratio than other formats for much of its life, and generally from having available capacities larger than other formats. CF cards can be used directly in a PC Card slot with a plug adapter, used as an ATA (IDE) or PCMCIA storage device with a passive adapter or with a reader, or attached various other types of ports such as USB or FireWire. As some newer card types are smaller, they can be used directly in a CF card slot with an adapter. Formats which can be used this way include SD/MMC, Memory Stick Duo, xD-Picture Card in a Type I slot, and SmartMedia in a Type II slot, as of 2005. Some multi-card readers use CF for I/O as well. Flash memory, regardless of format, can take only a limited number of erase/write cycles to a particular "block" before that block can no longer be written. Typically, the controller in a CompactFlash device attempts to prevent premature wear out of a sector by choosing the location for a piece of data at write time so as to spread out the writing over the device. This process is called wear leveling. When using CompactFlash in ATA mode as a hard drive replacement, wear leveling becomes critical. The advanced CompactFlash controllers spread the wear-leveling across the entire drive allowing all blocks to participate. The even more advanced CompactFlash controllers will also move the data that is rarely changed so that all blocks are worn evenly.
Technical details: NOR-based flash has lower density than newer NAND-based systems, and CompactFlash is therefore the physically largest of the three memory card formats that came out in the early 1990s, the other two being Miniature Card (MiniCard) and SmartMedia (SSFDC). However, CF did switch to NAND type memory later on. The IBM Microdrive format implements the CF Type II interface, but is not solid-state memory. CompactFlash defines a physical interface which is smaller than, but electrically identical to, the ATA interface. That is, it appears to the host device as if it were a hard disk. The CF device contains an ATA controller. CF devices operate at 3.3 volts or 5 volts, and can be swapped from system to system. CF cards with flash memory are able to cope with extremely rapid changes in temperature. Industrial versions of flash memory cards can operate at a range of -45 to +85 °C. CF has managed to be the most successful of the early memory card formats, outliving Miniature Card, SmartMedia, and PC Card Type I in mainstream popularity. The memory card formats that came out in the late 1990s through the early 2000s (SD/MMC, various Memory Stick formats, xD-Picture Card, etc.) offered stiff competition. The new formats were significantly smaller than CF, in some cases by an even greater fraction than CF had been smaller than PC Card. These new formats would eventually dominate the memory card market for compact consumer electronic devices.
Filesystems: There are varying levels of compatibility among FAT32-compatible cameras. While any camera that is claimed to be FAT32-capable is expected to read and write to a FAT32-formatted card without problems, some cameras are tripped up by cards larger than 2 GB that are completely unformatted, while others may take longer time to apply a FAT32 format. For example, the FAT32-compatible Canon EOS-1Ds will format any unformatted card with FAT16, even ones larger than 2 GB. Indeed, there is a FAT32 bottleneck because of the manner in which many digital cameras update the file system as they write photos to the card. Writing to a FAT32-formatted card generally takes a little longer than writing to a FAT16-formatted card with similar performance capabilities. For instance, the Canon EOS 10D will write the same photo to a FAT16-formatted 2 GB CompactFlash card somewhat faster than to a same speed 4 GB FAT32-formatted CompactFlash card, although the memory chips in both cards have the same write speed specification. The cards themselves can of course be formatted with any type of file system such as JFS and can be divided into partitions as long as the host device can read them. CompactFlash cards are often used instead of hard drives in embedded systems, dumb terminals and various small form-factor PCs that are built for low noise output or power consumption. CompactFlash cards are often more readily available and smaller than purpose-built solid-state drives and can be used to obtain faster seek times than hard drives.