I got the message "The following tracks and buses are currently assigned to a silent hardware output. The items listed below will be silent in your project until their outputs are reassigned to an appropriate hardware output." which seems to have caused many other users problems on this forum.

I got this message after I reopened a saved project I was working on from the day before (it was working fine then). So I played the project so I could hear what was silent. Nearly every track was silent apart from the very tracks which were supposed to be silent (according to the aforementioned dialog box). These tracks were output to Bus 'B' but the Bus 'B' itself was silent. The only way I was able to fix this was to clone every single track with the exact same inputs, outputs and sends and then they all worked fine.

Seems like a bug with the program to me - would upgrading to X2 resolve this? Or are there still silent bus issues in X2? Thanks, Mike.

Any circuit that leads to a bus that has an unassigned output will be listed there. Its not a bug. Its warning you that your project might not sound as you expect it to. We added this feature to allow users to trouble shoot problems like this. If you don't want the warning you can disable it via an ini setting. 
http://www.cakewalk.com/Support/kb/reader.aspx/20090221

The bus was assigned to Master as an output.
The fact that the error message appeared is not the problem. It's the fact that I had to clone all my tracks to get any output again.

I got a silent buss message the other day due not to a missing buss but due to a send set to none. One reason to check all you ins and outs when you get this message not just your buses. Turning that unused send off resulted in Sonar no longer giving me that message. 

 

Thanks John,
Yeah I found other people saying that having the sends set to none causes issues, so I went through all my tracks and made sure I deleted any sends that were set to none. Still resolve the issue though. I'm not even sure why there is an option for 'none'!