APFS Definition Stands for "Apple File System." APFS is a file system developed by Apple specifically for flash memory storage devices. It was released with iOS 10.3 in March, 2017 and for macOS 10.13 (High Sierra) in September, 2017. The Apple File System is the successor to Apple's previous file system HFS+, which has been used for decades in Apple products. APFS is designed to provide a more efficient means of storing and accessing files on flash storage devices, such as smartphone an...