the current version is 31.1.1

In my case Thunderbird starts up when I start up my computer, so there are a lot of background processes that are being performed and not just by Thunderbird, so the computer is otherwise engaged in checking updates etc. If you have an IMAP mail account then this also has to connect to many folders and download headers, maybe synchronise folders etc and larger folders take longer, so this could also impact on performance.

You may also have Anti-Virus software scanning your downloaded emails, so causing a temporary 'not responding' by thunderbird.

You could disable the scanning of emails, there should be an option to switch this off and keep the Anti-virus running.

Thanks for the reply.

I have only had this problem since the last version upgrade and after I had posted this question I noted that the version you mention had just been downloaded so I too have this version now.

I use POP3 accounts and have 'MS Security Essentials' installed and can see no facility for disabling emails if indeed it even does that.

Interestingly the newest version does not take so long to 'be ready' in fact the last three days or so it has been taking around 30seconds to load and 'be ready' to use.

So I will keep an eye on its performance then if it degrades again I will come back.

If you or anyone else can suggest things I might do then please do let me know,

I am grateful for the help in this matter.