Other
Scan for Disk Errors
Have your OS scan your drive to find bad sectors and other errors
Search Windows for cmd.
Right-click on Command Prompt when it appears.
Choose Run as administrator.
You may be prompted to confirm this decision. This is normal.
Enter the following command: CHKDSK /r
Restart your computer when you are ready for the check to be performed.
Open Disk Utility
In the menubar, click on View > Show All Devices
Select each listed device in the Internal section one at a time and click on First Aid
Running First Aid on your startup drive will temporarily make your Mac unusable until the process finishes.