Ira, I did the Apple Hardware Test and it is okay. Thank you for that.

Jon, The fan is behaving just now but if it starts to run fast, I now know what to do. Thanks. jaybass


OS 13.6.6 iMac (Retina 5K, 27", 2017, 3.4 GHz Intel Core i5, 24 GB RAM, 2400 MHz DDR4. SuperDuper. 1 TB Lacie HD