I am running an HP desktop under Linux Mint, and my installation of TB works flawlessly. My wife's install on a Lenovo ThinkPad T530, again running Mint, periodically, and at random intervals, suddenly stops working to replies to incoming emails. The incoming mail always works perfectly, but if one hits Reply to a message, a screen opens, with the message being replied to, properly displayed, but the Subject field frozen, and the text window to enter the reply equally frozen. When in this condition, attempts to send a new message to the sender, by going through the Address Book, choosing the recipient by name and then Write, has exactly the same issue - frozen input fields. The only resolution is to reboot the computer, when it all works normally until the next random freeze. (Closing TB and reopening it does not fix it.) Mint takes charge of updates of TB, and we have kept all updates up to date, as well as Mint itself, so I do not think this is an update issue. (We currently have TB 115.16.0esr) The problem happens only on the older Lenovo ThinkPad laptop, not on my HP desktop. Anything further I can add to document the situation? Any ideas, (other than "Reboot whenever it happens", (anywhere from a day or two, to weeks))?