I have decided after a few questions to make all this clearer with screenshots as users are slowing upgrading to Windows 10.
Upgrading to Windows 10 may have changed your regional settings - in particular the the date/time formats.
In some cases for the New Zealand region, the list separator has been changed from a comma to a semicolon.
Most relevant it appears is the am & pm format change under the New Zealand region.
If this is the case Cumulus will not start, throwing those dreaded error messages.
Below are the settings that will correct this.
The first 3 screenshots are the settings that have worked for some.
The second one is using the UK regional settings.
The third one is the settings I have.
This can be found: Start - Settings - Time & Language - 'Date and Time'
To check the List separator select 'Additional Date, Time & Region' at the bottom.
As in screenshot 4 below change this to a comma.
To change the am & pm select the Tab 'Time" in that same window.
This should read all lower case and appears to be the important bit of keeping Cumulus happy
a.m.
p.m.
What worked for me was changing the List Separator plus the am & pm settings. So try screenshot 4 and 5 first.
1- Suggested NZ Regional Settings2 - UK Regional Settings3 - Jennys Settings4 - List Separator5 - am & pm Settings