Are you using a Windows Classic Theme?

No, not using the classic theme, just new to TB so have not got into that sort of thing yet. Have been using outlook express for about 10 years. It is so frustrating not to be able to check for new messages on my Win 8.1 laptop. Installed TB on my Win XP pc at the same to replace outlook express and that works perfectly.

There are some problems with the progress bar when the Windows (not the TB) theme is a Classic Theme, but otherwise I can't think of any other reason why a new, add-on-free, installation shouldn't work. Unless the laptop has a different security program, such as the troublesome McAfee, compared to the XP PC.

Hi sfhowes - thank you very much for your reply. The laptop is in the as installed theme and windows 8.1 starts on the desktop. Both the laptop and the XP PC have the latest Norton Internet Security running. So it looks like I will have to put up with it for a while, but thanks again for your reply.

The issue so far was seen in Win 7, where the progress bar was distorted on a Classic Theme but not an Aero Theme. In Win 8, the Default Themes are similar to the Win 7 Classic Themes, and there are no Aero themes by default.

However, TB works fine here on Win 8.1 with either a Classic or custom theme. If, as a test, you were to install a (any) custom theme from the Windows site, I wonder if you would see any difference with TB.

Thanks again, just off for 2 weeks holiday, so will try a custom theme when I return. I have thought of reinstalling thunderbird to see if this resolves the progress bar and get mail issue.