Hopefully this thread is in the right forum...
I purchased a TASCAM US-4X4 audio interface a week ago that includes a registered Sonar LE.
i installed the Sonar LE properly but the software don't communicate with my audio interface...
It's outputs works good with my computer (Windows 10 x64 bit), but at first it showed the i/o drivers from my previous audio interface (Creavite X-Fi) and for an unknown reason the US-4X4 i/o drivers disappeared.
As I disabled the previous audio interface the Sonar LE still doesn't show me the i/o drivers...
 
ASIO4all didn't help and it messed up the playback from my computer.

ASIO4ALL should be avoided.  As you have found out it can mess up many things.  Best suggestion now is to use System Restore and restore the PC to an available restore date that is BEFORE you installed ASIO4ALL.
 
Check to verify the TASCAM is correctly installed and recognized by Windows (I assume you have Windows, you didn't state what OS/version you have).  Connect the TASCAM unit and then go to the Device Manager and display the Sound Section.  Check to see if it listed as one of the Sound devices and if it is shown as working OK or if it has an error code.
 
If it is shown as working OK, the TASCAM needs to be connected to Windows first before starting Sonar.  If you start Sonar first then connect the TASCAM unit, Sonar may not pick it up.

To add: After uninstalling ASIO4ALL you should install Tascams own ASIO-driver, if it isn't on your machine already. I assume such exist.
ASIO4ALL is not a real ASIO-driver, but a WDM-wrapper. It can be useful for folks using the motherboard soundchip (which seldom support ASIO), but otherwise a dedicated ASIO-driver is practically always the most recommendable option.

Kalle Rantaaho: I've already installed TASCAM's drivers in my computer and uninstalled the ASIO4all.
 
fireberd: I have Windows 10 x64bit (mentioned it already actually).
I verified that the computer recognized it as a sound device & an audio i/o - still no success with Sonar...
 
Thank you both so far!
 

Creative drivers are a known problem for conflicting with other ASIO drivers. 
I had to 100% remove all traces of the Sound Blaster drivers on my computer to get my Tascam to work properly so this is first hand info. 
And not only that now you need to totally get rid of all traces of asio4all which is another driver that can take over. 
 
Uninstall them and then search your computer for for any folders etc. I would run a registry cleaner like CCleaner too. 
Then install your Tascam drivers. 

Be sure and deselect all other drivers in Audio Preferences.  Asio only allows for one set of drivers - if it sees the Creative drivers first you won't be able to select any others.  Once your TASCAM drivers are at the top of the list, they'll stick there and no more problems.
 
And yea, ASIO for all are pretty weak and were made as a work-around.  Best to nuke 'em.

A common mistake that often gets made is connecting the usb cable first  to the computer before the drivers get installed. You should install drivers first, and let the driver installation prompt you to connect the usb cable to the computer, so then the computer can discover the new device.

When you first installed the TASCAM, did the Wave Profiler run? Probably not, since the Creative was registered already.
Try changing the Driver Mode to MME or WDM and run the Wave Profiler if you haven't already done so.

Dukey
Hopefully this thread is in the right forum...
I purchased a TASCAM US-4X4 audio interface a week ago that includes a registered Sonar LE.
i installed the Sonar LE properly but the software don't communicate with my audio interface...
It's outputs works good with my computer (Windows 10 x64 bit), but at first it showed the i/o drivers from my previous audio interface (Creavite X-Fi) and for an unknown reason the US-4X4 i/o drivers disappeared.
As I disabled the previous audio interface the Sonar LE still doesn't show me the i/o drivers...
 
ASIO4all didn't help and it messed up the playback from my computer.

See if this post doesn't solve your problem:


 
http://forum.cakewalk.com/FindPost/3233670
 
 

Please forgive, but the title of this thread made me do a double take...