If you are using VsVim then I had the same problem. Eventually worked out that I needed to change the VsVim Block Caret
display item under Tools > Options > Environment > Fonts and Colors > Display items. I changed the foreground color to 'Gray' and the background color to 'White' (which seems back to front) but that looks good for me on a dark background.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…