A blinking red LED on an enclosure may indicate that there is a “predicted fault” on the drive in that slot. Actual LED behavior will depend on the enclosure manufacturer. Refer to the user guide for your enclosure.

Such an error can result from a number of different factors, including a SMART error, read error, or cable error. The drive has not failed yet, but may fail soon.

For additional information about the LED indicators on an enclosure, see Enclosure Drive LED Status Indicators.