disk not ejected properly error message
I make iMovies for Youtube videos. Every day I transfer photos/videos from my canon dslr camera via an SD card into my iMac running High Sierra 10.13.6, then trash them off the SD card and have not had a problem until yesterday. Each time I transfer my photos/videos onto my hard drive, right click on the SD card icon to eject the card, the windows close and I take out the SD card. When coming back to the computer after it sleeps, I get an error message saying that the "disk was not ejected properly". I am assuming it was the SD card since that's the only thing touched.
Why is this? Do I need to reformat my SD card each time? I read somewhere that somebody said that a drive is operating in "failure" mode when this message comes up. What is that?