Ra ndom files are unusable

If your files are corrupting or becoming inaccessible, check your Mac’s storage isn’t failing. Internal drives incorporate SMART (Self-Monitoring, Analysis and Reporting Technology), which will alert you to developing problems so you can salvage your data before the drive becomes unusable. In Disk Utility, select the drive in the sidebar (not a volume on it) and check its SMART status at the bottom of the window. If it says anything other than “Verified,” back up your data and replace the drive as a matter of urgency.