You are trying to flash an image to microSD using your RPi?
usually its the dd method
unless somebody update me that Balena Etcher is available and running stable on Raspbian Stretch.....
"Don't come to me with 'issues' for I don't know how to deal with those
Come to me with 'problems' and I'll help you find solutions"
Some people be like:
"Help me! Am drowning! But dont you dare touch me nor come near me!"