What is the problem?
The 'copy all' button at the bottom of the terminal window only captures the first few lines of the log - not the entire thing as advertised.
What did you already try to solve it?
Clicked on 'Copy All', then pasted captured contents to Notepad++
Have you tried running in safe mode?
Did running in safe mode solve the problem?
serial.log or output on terminal tab at a minimum, browser error console if UI issue ... no logs, no support! Not log excerpts, complete logs.)
Additional information about your setup
OctoPrint version 1.3.6, OctoPi version unknown, printer M3-ID, firmware latest, browser Chrome, operating system Win10 Pro, ... as much data as possible
Clicking on the 'copy all' button seems to capture only the last few lines of the terminal log.