''<p>axel.moberg [[#question-1452117|said]]</p>'' <blockquote>'What on earth has happened to my Thunderbird. I've been using it for years. But maybe 7-8 months ago there was an upgrade. And ever since the software has been extremely slow in starting. It takes at least a minute to start andn look for incoming mail, even if there is nothing there. </blockquote> Since you are on Windows... * Start Windows in safe mode with networking enabled https://support.microsoft.com/en-us/help/12376/windows-10-start-your-pc-in-safe-mode * Still in Windows safe mode, start Thunderbird in Troubleshoot mode https://support.mozilla.org/en-US/kb/troubleshoot-mode-thunderbird How long is startup? Did the behavior change? ''<p>axel.moberg [[#question-1452117|said]]</p>'' <blockquote>And when I am reading a message and want to look in my inbox, I can't go there directly but have click on Contacts first. </blockquote> It's actually best to post unrelated items under different topics, so that the topic title reflects the question it contains. That said, this item doesn't make sense.