Can't install latest version of Dell Command update

DELL UPDATE APP NOT WORKING

My update app has failed for some time, so uninstalled, but can't install latest iteration as below, due to a previous version it insists is there still

Tried rebooting in SAFE MODE, but you can't install app in that mode.

Any suggestions to purge old version/s that are lurking somewhere?

Thanks.

'Dell-Command-Update-Application-for-Windows-10_DF2DT_WIN_4.1.0_A00
on my Windows10 64bit- on my  XPS 12 9Q33;