2010 21” iMac screen is green with vertical green bars on startup, will not complete login. No on screen options available, what to do?
iMac 21.5", macOS 10.13
Is that when holding the t key down at startup? Is it a Wired USB Keyboard hopefully?
Target Disk Mode and link to another Mac. If you can't get the logo of target to appear on the screen, then the graphics chip or video cable is damaged. Not an easy fix for that Mac.
https://support.apple.com/guide/mac-help/transfer-files-mac-computers-target-disk-mode-mchlp1443/mac
Apple logo does come up in background of the color bands, but it never fully loads and screen eventually goes black
Blank screen
