I did check RF etc .
However since RF has never an issue in the shack in last years.
Only after a win 10 upgrade did this happen [this may not have been the cause as all other programs migrated without issues ...
In any case I di did clean un- installed and re install plus check all settings from previous set up notes and now all back to normal and stable in the last few hours of operating.
the issue was that the com setting changed after each transmission god knows why ?
Thank you for your suggestion Jacques