When copying to system clipboard and it is unavailable due to some other application have locked it, DbVisualizer tries 5 times until giving up. The following should be in the DbVisualizer log (Tools->Debug Window) when this happens:


Could not acquire system clipboard after 1 tries. Will try again...

Could not acquire system clipboard after 2 tries. Will try again...

Could not acquire system clipboard after 3 tries. Will try again...

Could not acquire system clipboard after 4 tries. Will try again...

Could not acquire system clipboard after 5 tries. Will try again...

Could not acquire system clipboard after 5 tries. Giving up!

Uncaught exception: java.lang.IllegalStateException: cannot open system clipboard


So the problem is that there is another application using the system clipboard. If the problem persist, try closing down tool by tool until it works.