Apple is servicing 13 inch non Touchbar MacBook Pros sold between June 2017 and June 2018 that contain a 128GB or 256GB solid state drive, which have an issue causing data loss. To see if your Mac is affected, visit this page and enter your serial number. If you take your computer in to be serviced, back up your entire computer first with Time Machine to an external drive. Alternatively, have a professional such as MacLab do this for you. Apple will replace the drive and return the computer to you with system software only. Your data will not be present. You (or a professional) will need to restore the data.