What steps will reproduce the problem?
1. Open test1.xmind by double click on the file
2. Open attachment from it
3. Open test2.xmind by double click on it
4. Try to open attachment from test2.xmind - does not work for me.

Close xmind, and open just test2.xmind - it works OK.

What is the expected output? What do you see instead?
Should open attachment as expected.

What version of the product are you using? On what operating system?
3.0.2, Windows Server 2008, SP1