Initially upon opening Thunderbird, I can select and read messages in whatever folder I open initially, but Thunderbird will no longer allow me to select other folders. If I open in Sent, I can't select Inbox and vice versa, for instance. And once I try to shift to another folder, the Thunderbird folder I am in freezes so I can no longer select emails in that folder. I can send and receive messages, so that is some consolation. The problem is not being able to manage email. Also, I can only delete a message by going to the top menu and selecting Delete from the dropdown Edit option. Once the inbox freezes, the mouse functions ceases to work in Thunderbird. Any help would be appreciated.