Camtasia Recorder failed to start recording

Hi,
I cannot start to record my screen cause of this error. The program worked fine until now and also this is the first error that Camtasia gives. Since I never experienced such an error before I don’t know how to solve it so can anyone help me please to fix this one ?
Thanks !

Camtasia Recorder
Failed to start recording: : Temp Folder Uninitialized
OK
