Abstract: A memory system includes a memory controller configured to write data in a first mode to a first block of a first area of a non-volatile memory. The first mode is a write mode for writing data with a first number of bits per memory cell. The memory controller is further configured to execute copy processing on the data written in the first mode to the first block, by writing system data written in the first block to a second block of the first area in the first mode and writing user data written in the first block to a third block of a second area of the non-volatile memory in the second mode. The second mode is a write mode for writing data with a second number of bits larger than the first number of bits per memory cell.