Outcomes

Incomplete Set

The "set" skin set is only partially skinned, missing: missing elements.

Cause: One or more elements of a skin set are present, but a required element of the same set is missing.

Mixed Spinner Style

Both old ("old file") and new ("new file") spinner style elements are present; the old style will take priority.

Cause: Elements exclusive to both the old and new spinner styles are present at the same time.

Duplicate Hitburst

"path" and "path" are identical; hit100/hit300 hitbursts must be visually distinguishable from their geki/katu counterparts.

Cause: hit100 or hit300 shares the exact same file as its corresponding katu/geki hitburst.

Missing Slider Border

difficulty skins hitcircle or slider elements but does not define a custom slider border colour (SliderBorder under [Colours]).

Cause: A custom slider border colour must be selected when a beatmap contains skin elements from the hit circle or slider sets.

Similar Slider Colours

difficulty's slider body colour (SliderTrackOverride) is too similar to its slider border colour (SliderBorder).

Cause: The slider body colour is too close to the slider border colour, making the border lose its purpose as a visual boundary.

New Spinner Style

"path": usage of the new style spinner is discouraged; it only displays correctly if the player's "Preferred Skin" is set to Default.

Cause: Elements exclusive to the new spinner style are used, which is only recommended when a default skin is forced.

Deprecated Spinner Osu

"path" only displays for players using skin version 1.0, which is extremely rare; consider removing it.

Cause: spinner-osu.png only works with skin version 1.0, while essentially all modern user and default skins use version 2.0 or higher.

Non Png

"path" should be a .png file if it uses transparency.

Cause: A skinned gameplay element does not use the .png format, which is required for elements that utilise transparency.