I've just copied* my Thunderbird profile from my desktop to my (only occasionally used) laptop, and everything appears to have copied just fine (i.e., all settings are there, as are all my folders of old mail, and recently received emails appear in the inbox). But I can't connect to the mail server. The Thunderbird message is : "Could not connect to [twc server name]; the connection was refused." I know there's nothing wrong with the server because I downloaded mail to my desktop shortly before copying the profile and again shortly after getting the problem message on my laptop. I've copied my profile in the past when I need to use my laptop (about 3-4 times per year when I travel and need current and recent emails). And it's always worked just fine before, so I'm totally confused. Two things to mention, if they happen to be pertinent: (1) My desktop is still on W10 1909, and the laptop's on 20H2. And (2) Thunderbird was installed (by the Thunderbird installer without intervention by me) to the Program Files (x86) folder on my desktop, but to the plain Program Files folder on the laptop. *Again, I went through the copying steps I've always used before: (1) copying the Thunderbird folder and subfolders from the C:\users ... \roaming folder of my desktop to the roaming folder on my laptop, and (2) just copying the contents of the jibberish-named profile folder from my desktop to the different jibberish-named profile folder on my laptop. Any advice would be much appreciated. I will have to replace my desktop soon (it fails miserably every time I try to install Windows 10 20H2), and I really need to be able to use my laptop for email until I get a new desktop up and running (and now I'm frightened I won't be able to copy my profile to the new desktop!).