Hey Ahmed

To check if a loop is closed or not, check the Properties of the lines (PR).

The fastest way to join or close lies is by joining(J) and trimming(TR); using the fillet(F) Command and setting the radius of the fillet to zero(0).

Yes, It’s a pain sometimes, just keep trying to do it, from the angle point

Did anyone manage to find a good portable version? link plz

type -dwgunits at the command prompt.

Enter the values pertaining to the drawing’s units.

When prompted with, “Scale objects from other drawings upon insert? [Yes/No]”, type N, Enter.

That should stop scaling of objects upon insert.