Windows 11 Pro (64 bit); C Cleaner version 6.05. 10.1110 - Free
Persistent error & unable to remove CLSID. Screenshots attached. When I look the CLSID in Regedit , Regedit error: Cannot Delete (See Screen Shot).
The speech runtime toast notifier could be deleted from the registry - but Windows would just put it straight back again.
It's one of those things with Windows. I believe that the notifer is an integral part of Cortana, (and possibly even used by Edge?)
Just right-click on it and make it an Exclude in CCleaner then it won't bug you anymore.