system
15
Just an update. Haven’t had any problems with currently flagged issue for ages now (he says this very quietly, under his breath) 
I’ve had about 3 or 4 more blocks of the “CreateFile(pszHead) error C:\Windows\TEMP_avast_ 32” error message documented in the mail.log… but haven’t actually witnessed any problems with not being able to download emails.
Seems that the full uninstall and reinstall may have fixed the issue.
Please note that I tried running the avast uninstall utility too, after the uninstall, initially in safe mode (where it did nothing i.e. it ran but nothing additional happened - I was kinda expecting to see some messages about registry key deletion, etc… as most software seems to leave remnants behind)… then ran it in normal desktop mode too (despite the warning that using in safemode is better).
Not saying that this is significant in the apparent resolution of my problem but just documenting what I did.
I’m currently on 32bit vista home premium, with avast 2014.9.0.2011 and virus defs 140116-0
Cheers,
Gary