Hi there ...

I am trying to:
Open file A .. success ... open file B ... crash
Restart Icad
Open file B ... success ... open file A ... crash
Restart Icad
Open file A ... success ... open new session of Icad ... open file B ... success

File A and B both can open on their own Icad session. But it crashed when both open in one session of Icad
tried to open with recovery ... no lucky

Not happen before I update to 12.1.243.153262

Need help please

Have you tried to open both at the same time?

File>Open> select/highlight BOTH files > Open

Trying that and still no lucky.
Uninstall and install previous version.
Works ... ca open multiple files now ... but ...

When I rotate UCS and work with it ... there is a problem with copy command.
I can't easily copy an object multiply with ortho ON
With ortho OFF, objects can copy easily
I think ... Specify second point or [Array/Exit/Undo] <Exit>: ... loose the base point