Thank you for contacting Presonus Technical Support. Sorry to hear about the recent issues you have been experiencing.
Make sure in Studio One > Preferences > Advanced > Services that External Device Support is enabled.
Also, check out this troubleshooting guide from M-Audio: http://m-audio.com/kb/article/1619
Please create a support ticket if you would like to discuss this in more detail.
Here is a link to create a ticket: http://support.presonus.com/hc/en-us/requests/new