Hi, There are no other entries saying 'STLS connection detected'. It is all as I described yesterday. But here are a few copied extracts from yesterday including messages above and below them in the log:
03/11/2014 13:32:57.107 Safari[1194]: CGContextSynchronize: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update.
03/11/2014 13:36:39.394 com.avast.proxy[1017]: Defective POP3 response!
03/11/2014 13:36:39.394 com.avast.proxy[1017]: PLAIN
.
03/11/2014 13:36:39.395 com.avast.proxy[1017]: Defective POP3 response!
03/11/2014 13:36:39.395 com.avast.proxy[1017]: PLAIN
.
03/11/2014 13:36:41.342 com.avast.proxy[1017]: Defective POP3 response!
03/11/2014 13:36:41.342 com.avast.proxy[1017]: PLAIN
.
03/11/2014 13:36:41.344 com.avast.proxy[1017]: Defective POP3 response!
03/11/2014 13:36:41.344 com.avast.proxy[1017]: PLAIN
.
03/11/2014 13:37:35.644 com.apple.launchd[1]: (com.avast.update) Throttling respawn: Will start in 5401 seconds
03/11/2014 13:47:26.583 com.avast.proxy[1017]: Defective POP3 response!
03/11/2014 13:47:26.583 com.avast.proxy[1017]: PLAIN
.
03/11/2014 13:47:26.585 com.avast.proxy[1017]: Defective POP3 response!
03/11/2014 13:47:26.585 com.avast.proxy[1017]: PLAIN
.
03/11/2014 13:47:26.587 com.avast.proxy[1017]: Defective POP3 response!
03/11/2014 13:47:26.587 com.avast.proxy[1017]: PLAIN
.
03/11/2014 13:47:26.587 com.avast.proxy[1017]: Defective POP3 response!
03/11/2014 13:47:26.588 com.avast.proxy[1017]: PLAIN
03/11/2014 13:47:35.612 com.apple.launchd[1]: (com.avast.update) Throttling respawn: Will start in 4801 seconds
03/11/2014 13:50:19.626 launchservicesd[54]: Application App:"Avast Mac Security" asn:0x0-43043 pid:1751 refs=7 @ 0x7f993845d860 tried to be brought forward, but isn't in fPermittedFrontApps ( ( "LSApplication:0x0-0x45045 pid=1759 "SecurityAgent"")), so denying. : LASSession.cp #1481 SetFrontApplication() q=LSSession 100004/0x186a4 queue
I have since disabled Avast's Mail Shield so i can get round the problem - but obviously that wasn't my original intention!