Followed directions on moving profile to new computer. All accounts and messages moved over with no problem. New laptop is Dell Precision i9 ultra with 2tb ssd + 1 tb ssd secondary, 64gb ram running under Win 11 Pro. I have 5 accounts mostly gmail and hotmail with about 18gb of emails (including attachments). Ran fine with older laptop running Win 10 even with cad, tbird and streaming video at the same time. Tbird is slow running by itself but if I open Rhinoceros 3D cad program, then open Tbird to read an email it becomes really slow, lag, stutter and affects performance of entire system. Tried numerous fixes and rebuilding index helped quite a bit, but when I use my main program (Rhino 3D) then use tbird it still slows dramatically. Any ideas appreciated :-)