Short description of error
List of workspaces in user configuration sometimes is empty. Should never be the case.
If no workspaces.blend is found in the user configuration itself (which must never have 0 workspaces), the bundled default one is used as fallback (should be in [build_dir]/[release_dir]/datafiles/).
The user who reported this did have the bundled workspace.blend in the right place, so this is not the cause.
Exact steps for others to reproduce the error
- Launch Blender from command line
- Press "+" button to add a new workspace
- If appearing menu only contains "Duplicate Current", there's the bug.
Mainly leaving this here for myself.