There is, the same option as the record timing.
However if I click OK in the preferences (with or without changing anything) I get an error and then the input and output boxes go blank. Thought it was only if I changed something, but apparently not.

What exactly does the error message say?

Just unplugged, uninstalled, rebooted, installed, plugged in, rebooted.
It now isn't showing an error. It's just wiping the list. Open prefs, its there, close them and re-open, blank list.

so if I dont open the prefs and I go FILE, NEW I get this:

For now, unplug everything else USB that you can.  Also make sure the TASCAM isn't sharing a hub with other devices.
 
Did you ever delete AUD.ini?  Or start SONAR with CTRL-SHIFT?
 
 

I dont use a hub and I delete the AUD.ini after each reinstall of the drivers/software.
USBs - keyboard, mouse, webcam, wireless phone charger, tascam, USB3 external HDD cable (nothing plugged into it but when I need it, it saves my pulling my PC out).
I'll unplug charger and webcam, reinstall, wipe aud.ini and try again with those 2 things unplugged.

There are also internal hubs ...
 
 

After scanning the thread I'm going to toss out a general troubleshooting tip I've learned about "disappearing" audio devices. It may help and it may not.
 
Simple version: Make sure the audio interface's "power" is turned ON and the USB cable is connected BEFORE launching SONAR.
 
In my experience if connected and properly installed Audio and MIDI devices are not appearing in the appropriate SONAR devices areas it is usually because I did not give Windows and the device drivers enough time to fully load before opening SONAR. Because of this SONAR doesn't see the devices when it first opens and thus the devices aren't on the list(s). If I close SONAR, wait a while (or reboot), check my connections and whatnot the devices will appear as expected.
 
So...
 
1) Boot up and wait a minute
 
2) Connect/power up your audio/MIDI devices and wait a minute
 
3) Open SONAR and if you allowed enough time for your devices to get their shiz sorted out then everything should be available
 
 
Also... another rule of thumb I follow is to ALWAYS use the same USB port on your computer that you installed a device on. So let's say you have 3 USB ports on your system. You fully install your audio interface on USB port 1. ALWAYS plug your interface into that port from now on. If you install a MIDI keyboard on USB port 2 always use port 2 for that device... and so on.
 
It MAY not cause problems if you don't and at this point it may not be relevant but since I've adopted both of these habits I NEVER seem to lose my devices in the SONAR Prefs.
 
Hopefully that shakes something loose.
 
Cheers.

Thought you were talking about external.
I have mouse and keyboard plugged into 1 pair.
Tascam plugged into pair 2 (was with HDD cable)
pair 3 empty (was webcam and phone charger)
 
Opened prefs, check devices listed, check master. both options have tascam in it this time. close it off, go FILE, NEW, get this popup:

Cheers beepster. Sometimes the simple stuff can easily be overlooked and after several hours of facesmashing desk it ends in severe facepalming due to something exactly like that.
You're right but unfortunately I was already following that rule of thumb. Even mice can have hissy fits when plugged into a different usb port.
 
Its more that the devices are there at the start but disappear if I try to make a new file or open and close the prefs.