My problem is that ZoneAlarm has started blocking Thunderbird from communicating with the net.
I have been using ZoneAlarm Free Edition with Mozilla Thunderbird satisfactorily together for several years, until three or four weeks ago.
I am fairly sure the problem lies with ZoneAlarm becaise :-
All other programs, including Mozilla Firefox, seem to work normally, and
The problem can be "avoided" by switching off the Application Control element of ZoneAlarm..

I have read somewhere (here ?) that the problem can be caused by the affected program's listing in ZoneAlarm being out of date.
That would appear to be the case, as Thunderbird is running version 17.0.3 and the ZoneAlarm listing for it is version 7.0.1
The ZoneAlarm version running is which was issued recently ( January ?). That would more or less coincide with the start of the problem.

I understand the remedy is to find, highlight and delete "Thunderbird" in the Application Control list, and so allw ZoneAlarm to "find" it again.
The problem with that is that, whilst the deletion may appear to have worked at the time, the deleted entry is back again next time the list is opened.
How do I get rid of it for good ?

Also, what would be the best way to delete the whole list and start afresh ?
I note that my Application Control program list contains 900 entries, and that a high proportion of them have identical or similar names.
There are, for instance, 28 entries simply called "Setup.exe" without including those such as "Setup installer" which include the word.
I am sure that most of these entries are redundant, and that a fresh start would be no bad thing, but are there any obvious problems ?
I see there is a "Reset to Default" option in Preferences - is that what I want ?