Does this happen when you open a database file or also when you launch FileMaker without opening a file?
If only when opening a file, is it always the same file? (Try creating a small test file and see if you can open it without freezing.)
Ill I do is lunch the application. I have been testing a few things here gos.... When I log in using the user that is having problems in Safe Mood it works. When the user is logged in normaly it does not responed again.