Tools/Preferences --> hung, with no option to recover. Had to kill the process and try again. Repeatable. Even with no MM file open.
When I removed my "C:\Users\userid.freemind\auto.properties" file, it then worked.
Software suggestion: make the software more robust-- at least print some indication of the error or possible work around. As it was, there was no hint about what it could be. Nothing in the log that I found.
I'll attach my properties file that seemed to cause the problem.
Freemind: 1.0.0 RC4
OS: Windows 7 Professional