Defense+ seems not to be "saving" safe files

I am having a problem with Defense+: when I run some programs, I receive an alert that the file can’t be recognized and that it will be sandboxed.
I use Expression Blend, from Microsoft, which crashes when in a sandbox.
The problem is: I click on “don’t isolate this file again”, or I open the pending file window, submit it, do a lookup (which returns that the file is safe) and manually move it to trusted files, but when I restart the program, it can’t be recognized and is sandboxed again. It seems that Defense+ is not saving the files as trusted.

That happens to many other files, I get this “file can’t be recognized” pretty often and always to the same files. But I can’t manage to make Defense+ accept it.

Am I doing something wrong?


Edit: just found a similar thread here:
But I can’t delete this one, sorry for the confusion…

No problem.

Did the solutions suggested there work for you?