09-06-2021, 07:36 PM
Quick summary 
Using Win10 / Gimp 2.10.24-revision 2 (note the current latest is revision 3) and fuzzy select selects nothing.
The flashing pink (magenta) sounds like you have the Draw Mask toggle on, dragging the mouse adjusts the threshold and you might be selecting everything or nothing. 30 second example https://i.imgur.com/UrPR7vQ.mp4
Otherwise, post a screenshot of your image +layers + tool options
Revert to Gimp 2.8 ? No stick with Gimp 2.10
Using Win10 / Gimp 2.10.24-revision 2 (note the current latest is revision 3) and fuzzy select selects nothing.Quote:..But in my case, Gimp flashes all in pink, marching ants on BACKGROUND visible, but fuzzy select selects nothing, nada. Not even with toggle quick mask - which too seems to do nothing.
The flashing pink (magenta) sounds like you have the Draw Mask toggle on, dragging the mouse adjusts the threshold and you might be selecting everything or nothing. 30 second example https://i.imgur.com/UrPR7vQ.mp4
Otherwise, post a screenshot of your image +layers + tool options
Revert to Gimp 2.8 ? No stick with Gimp 2.10