Situation: Spybot-S&D immunizes Internet Explorer, for all user profiles.

Experienced: also system account profiles are immunized, especially:

Local Service
Network Service
SystemAlso known as S-1-5-18, S-1-5-19 and S-1-5-20 (previous to Helloween Edition beta 2, no account names, just these IDs, were shown).

Expected: do not immunize those, as Internet Explorer will very very likely never run under those accounts.

For those who still want it: use tweak ImmunizeSystemAccounts set to 0x000001.

I think this may relate to something I am chasing with version 1.5.19, 7853 unprotected items under the catagory of Windows Global Hosts, but I don't understand your reference to "For those who still want it: use tweak ImmunizeSystemAccounts set to 0x000001"

Can you please explain?

Unprotected items are usually because other security applications block the immunization, like for example ZoneAlarm, which protects the hosts file against changes.

A tweak means to create a registry REG_DWORD value of the specified name and value in HKLM\SOFTWARE\Safer Networking Limited\Tweaks. But this is unrelated to your hosts file problem!

Thank you, tried it and now understand it.