What Is Runtime Packed FSG?

"Runtime Packed FSG" was created to compress certain applications into smaller sizes. In fact, FSG stands for "Fast Small Good." It is not the same as a runtime error and it will not damage your computer.

You may have seen Runtime Packed FSG in your anti-virus software and you might be wondering why it's there. Why is your anti-virus software scanning for something that isn't harmful? The reason is because many virus creators use Runtime Packed FSG when packaging their viruses to be distributed. It makes them smaller and harder for anti-virus software to detect.

More legitimate software developers previously employed Runtime Packed FSG but now it is used to a lesser extent because there are better packaging functions. You might not even find that much information about it online because people don't usually have a problem with it. Your anti-virus software simply makes a note that it has been used in the past and watches out for it.

A more current software-packaging program is called PE Compact. PE Compact shrinks Windows files, including DLL, EXE and SCR files, to name a few. It significantly compresses them and then quickly decompresses them once they are on the computer.

Back when the FSG was being used for good, and not for evil, the anti-virus software programs that were on the market did not have it listed as a potential threat. Virus creators took advantage of this and appropriated the FSG packaging for their malicious content, kind of like a Trojan horse. So now your anti-virus software watches out for it and if it is detected on your computer you will be advised to delete it. Most of the time, this is unnecessary. Sometimes the detected file is located in your system's cache. It is usually harmless but you could always delete it simply to free up some room.

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