Two CorelDRAW instances
Running two CorelDRAW windows works, with one rule: the add-on talks to the machine through a single channel, so only one instance sends at a time.
What happens when you open two
Each CorelDRAW process loads its own copy of the plugin. Both windows can trace, mark and arrange normally. But the channel to the machine tooling is exclusive — the first instance to attach owns it, and the second cannot.
Symptoms
- The second window shows a “cannot load DtzCdrToolCore.dll” message, even though the file is present.
- Sending from the second window reports success but the machine never moves.
- The device list is empty in the second window while it is fine in the first.
Working with two documents
- Do the tracing and layout in both windows — that part is independent and safe.
- Send from one window only. If you need the other document, send the first job, then close the first window and work in the second.
- If you must switch back and forth, close the idle window instead of leaving both open. A closed instance releases the channel immediately.
Why it is designed this way
Two senders writing into one machine buffer would interleave paths with no way to tell them apart. Exclusive access is the cheaper guarantee: the job that starts is the job that finishes.
Quick self-test
If you suspect the channel is stuck, close all CorelDRAW windows, confirm no CorelDRW.exe remains in Task Manager, and start one instance. If sending works again, the cause was a second instance.