Hi all, looked around but did not find the exact issue. I often need to perform actions on many messages in a folder (move, delete etc). Just the act to select many messages (ctrl-A or Shift-Mouse Left button) brings TB to go in "not responding". The time waiting is proportional to the number of messages selected (hundreds or even thousands) Selecting few messages makes the waiting marginal. The issue is the visualization of the messages list preview in the preview pane, hiding the preview pane the selection is very fast. It happens also in folders with relatively few messages (tens). It does not happen on a laptop using the same messages environment. I tried in safe mode, no add-ons etc etc nothing changes this behavior I have no AV running. Windows 10, TB 52.3 What else can i try? Thanks in advance, Alex