Windows Live Mail takes ages to start up

Question

I am running Windows 8.1. with Windows Live Mail as my email client. I am unable to understand why now it takes WLM ages to start up. Before it used to startup in less than half a minute. Now from the time that I click the icon on my desktop, almost 10 minutes elapses before it starts up.
Is it probable that the latest Windows updates (which I had just downloaded) could be the culprit as previously, on two occasions, after downloading Windows updates, I had similar problems (the machine would not even boot) and I was advised to Refresh but that deleted all my email messages in both the POP and Imap accounts. In consequence, I had to re-create all my accounts afresh but when I connected to the internet and downloaded the messages, only message headers were recovered when imported but not the tax. I therefore do not wish to Refresh yet again.

What could be the problem? If the only solution is to Refresh once more, how do I backup all the messages in the respective folders of all the accounts (I have two POP accounts and three Imac accounts) and then, after a Refresh and re-creating all the accounts yet again, how do I restore the messages in the respective folders?
I have even run a scan with Malwarebuytes Antivirus as well as with Windows Defender but the results were negative. No threats were detected. What then could be the problem?

I asked this same question also on two other Forums including Microsoft Community but no one has come up with a solution. It seems it's got everyone stumped but I hope there is someone on this Forum who can pinpoint the problem and come up with a solution. All responses would be appreciated. Thanks.