Standard key signatures are available in the Key Signatures palette in the Basic or Advanced workspaces. You can also create custom key signatures using the Key signatures section of the Master Palette (press Shift+K to view), which also allows you to use a wide range of non-standard symbols.
Add a new key signature
Add new key signature to all staves
- Drag a key signature from the palette onto an empty part of a measure, OR
- Select a measure and double-click a key signature in the palette, OR
- Select a note and double-click a key signature in a palette.
Add new key signature to one staff only
If you wish to change the key signature of only one staff line, leaving others unchanged:
- Press Ctrl (Mac: ⌘) and hold while you drag a key signature from a palette onto a measure.
Replace an existing key signature
Replace key signature for all staves
- Drag a key signature from the palette onto the key signature to be replaced (or onto the measure containing the key signature), OR
- Select the key signature to be replaced, and double-click a new key signature in a palette.
Replace key signature for one staff only
If you wish to replace the key signature of only one staff, leaving others unchanged:
- Press Ctrl (Mac: ⌘) and hold while you drag a key signature from a palette onto the key signature to be replaced (or onto the measure containing the key signature).
Remove a key signature
- Click on an existing key signature and press Del, OR
- Drag the empty key signature from the palette (in the advanced workspace) onto the measure.
Courtesy key signature
In the Inspector for a selected key signature, there is an option for "Show courtesy." Additionally, Style → General... → Page has on option for "Create courtesy key signatures". The Inspector will affect only the selected one; the style setting will affect the entire score.
Naturals on key signature changes
By default MuseScore only shows naturals when changing to no signature (C Maj/A min). In all other cases, it simply shows the new key signature:
You can choose whether to show natural(s) in certain cases when changing the key signature. Under Style → General... → Accidentals you'll see the options:
You can Apply the changes, or click OK. If you are in a linked part, rather than in the primary score, you can use the Apply to all parts button.
The option 'Before key signature if changing to fewer ♯ or ♭' yields this result:
The third option 'After key signature if changing to fewer ♯ or ♭. Before if changing between ♯ and ♭' produces the following output:
Key signature and multi-measure rest
Multi-measure rests are interrupted, if there is change in the key signature.
Courtesy key signatures and section breaks
A courtesy key signature will not be shown at a section break.
See Break or spacer: Section break
Custom key signatures
Press Shift+K to bring up the Key signatures section of the Master palette.
The left panel contains a library of key signatures. To the right is the Create Key signature panel where you can customize key signatures by dragging accidentals from the palette onto an appropriate location in the staff above. When completed, press Add to move the new key signature into the library. Clear cancels the custom key signature and allows you to start building again from scratch.
A full range of accidental symbols is available—both conventional and non-standard (such as half-flats, half-sharps, etc.).
Note: Playback of custom key signatures is not currently supported.
Key signatures in the Master palette can be moved to a custom palette in a user workspace by dragging and dropping. It is also possible to apply key signatures to the score directly from the Master palette by either selecting a measure and double-clicking a key signature, or dragging the key signature onto a measure.