Occasionally, the Symphony entry in Apps & Features becomes a residual entry within Registry Editor which you cannot uninstall (Figure 1):
Figure 1 Uninstall Error
Remove a residual Symphony entry from Registry Editor by following these steps:
1. Open the Registry Editor from the Start menu (Figure 2):
Figure 2 Registry Editor
2. Navigate to the following URL and remove the Symphony folder (Figure 3):
Figure 3 Symphony folder
3. The residual version of Symphony will be removed from your machine.