Stop Mac Adding a Shadow to Window Screenshots

Screenshot a window on Mac and the saved PNG comes out far larger than the window itself. That extra area isn't blank — it's a band of transparent pixels holding the drop shadow, roughly sixty pixels on every side. If you care about file dimensions, alpha channels, or getting captures to line up in a grid, that invisible padding is a real nuisance. One setting stops macOS adding it, so the image matches the window exactly.

What the padding actually is

In window-capture mode (Shift+Cmd+4, then Space, then click), macOS composites the window onto a transparent canvas and draws a soft shadow into the surrounding pixels. The result: a PNG with a live alpha channel and dimensions that can be 120 pixels wider and taller than the window. Because the shadow's spread scales with window size, no two captures share the same padding, which is exactly what makes them awkward to work with downstream.

Where the transparent padding bites

• Dimensions don't match the window. A 900-px window can save as a ~1020-px image, throwing off any layout that expects the capture to equal the content.
• Alpha causes surprises. Tools that flatten transparency onto white, or that trim by alpha, treat the shadow inconsistently — sometimes a grey fringe, sometimes an over-aggressive crop.
• Grids and collages misalign. Variable padding means visible edges never sit on the same gridline, so assembled sheets look ragged.

Stop the padding for good

Disable the shadow and captures crop tight to the window — no transparent border, dimensions equal to the visible content:

# Window captures with no shadow padding
defaults write com.apple.screencapture disable-shadow -bool true
killall SystemUIServer

killall SystemUIServer reloads the capture service so it takes effect at once — no logout required. To restore the padded, shadowed default:

# Put the shadow (and its padding) back
defaults write com.apple.screencapture disable-shadow -bool false
killall SystemUIServer

The behavior is identical across macOS 13 Ventura, 14 Sonoma, and 15 Sequoia.

Skip it for a single capture

Need one un-padded shot without changing the default? In window mode, hold Option as you click the window. That capture crops tight; the rest keep their shadow. Handy when only one image in a set needs exact dimensions.

Trim the padding on shots you already have

Disabling the shadow only affects new captures — files you shot earlier still carry the padding. To tighten those, see how to crop and resize screenshots in Preview on Mac and trim them down to the window in seconds.