The letter D doesn't work when I work in Indesign.

[Wietske5EE6]

I am setting up a manual with a table of contents and am working with paragraph styles for the first time in Adobe Indesign.
All of the sudden, for some reason, the letter D does not work.

Anyone have any idea how this could happen and be solved?

[jmlevy]

What happens when you press the D key? Nothing? A warning message? If a paragraph style is applied when you press D, it is because you have assigned this key as a shortcut to apply the style.

[Eugene Tyson]

I agree with @jmlevy 

You might be able to see what happened if you go to Edit>Undo there might be an Undo state in there when you press D.

Alternatively to JMLevy - you might have a 3rd party product installed on your computer that is overriding the D button.

You could try resetting your preferences:
The easiest way to reset everything is to delete the InDesign preferences: as soon as InDesign starts to boot hold down Shift, Alt, Ctrl (and Apple/Cmd if working on a Macintosh). A dialog will appear asking to delete the InDesign Preferences, select 'Yes' on this dialog.
Further info and instructions here if needed:
https://helpx.adobe.com/in/indesign/kb/indesign-preferences-support-file-locations.html

[Wietske5EE6]

Thanks both of you, I have deleted all the paragraph styles as well as resetting everything and the letter D now works again 😄