As always, strictly an Elements Windows person here.
In the Premiere Elements Windows world USB microphone are rarely if ever supported. What type of microphone is your
Samson C01U? A Google search seems to say that it is the USB type.
That may or may not be the case in the Mac experience.
Also, in your Premiere Elements 12 Mac system, do you have Edit Menu/Preferences/Audio Hardware with its ASIO tab under which are Input and Output tab/settings or the counterpart of those settings in Mac?
The forum moderator Steve Grisetti used Premiere Elements Mac so perhaps he can steer us in the right direction on finding the core of your Premiere Elements Mac audio issue.
Is this a "it worked before but not now" or "it never worked before"?
Add On...I am not sure if information as found in the following link would help.
If you have been there and done that, please excuse the inclusion of it.
Although the Windows configuration portion of my free tutorial may not be helpful, watch the segment on configuring the Premiere Elements ASIO settings.