If you cannot use the MP tool immediately, you can try basic system fixes: FIX USB Flash Drive Unknown Capacity
: Many generic drives reporting "Unknown [FA00]" are counterfeit. For example, a drive sold as 64GB might only contain an 8GB memory chip. After using AlcorMP, the drive will revert to its true physical capacity . alcor micro unknown fa00 f w fa04 top
The identifier is a technical diagnostic report typically generated by tools like ChipGenius . It indicates that your USB flash drive's internal controller is from Alcor Micro , but its firmware (F/W) or Flash Translation Layer (FTL) is corrupted, leading to the "Unknown" status . If you cannot use the MP tool immediately,