Thanks, yes, that solved it. I uninstalled 20.0.7. Downgraded 21.0.2 to 21.0.2, then re upgraded back to 21.0.3.
Tilt Shift is working fine now. Thanks.
Only problem now is I lost all my User settings, Actions, Workspaces, ThirdParty Extensions, et al, and I will have to find them to get back to my former status.
PS: regarding above solution: For anyone using this solution and to avoid losing User Settings, Extensions, etc.
If deleting an earlier (duplicate) version, the dialogue box offers an alert to Keep or Remove earlier version User Settings. You should select the 'Keep' earlier version settings, then the problem I had with lost settings is avoided.
Since I did a full Backup of C:\ drive last night, this morning I was able to restore to original state and re-delete my earlier (dulicate) version with the Keep settings option. Now all is perfect !