I was about to upload a song to youtube and can't find youtube publish in my export options. It was there a couple of months ago, unless I'm doing something stupid. I'm hoping for stupid.

Can someone check in the export window if the youtube publish option is there?

File > Export > Video 
 
For file type, save as YouTube Publisher. Wait a bit, and the publishing screen will appear.

That doesn't work. Video is greyed out. The manual says to use File>export>Audio and then select youtube publisher from the drop down menu, but it's no longer there.

To publish audio to YouTube
1.               
Open the SONAR project you want to publish to YouTube.

2.               
Go to File > Export > Audio.

3.               
In the Files of type list, select YouTube Publish.

4.               
Enter a file name in the File name box.

5.               
Click Export.

Cakewalk YouTube Publisher opens.
6.               
Enter the required settings in Cakewalk YouTube Publisher (see Cakewalk YouTube Publisher interface), then click Upload.
 
3. YouTube Publish isn't in my files of type list?

I don't think you can publish to YouTube if the file doesn't contain some kind of video. That's a YouTube requirement, not SONAR.

I've done it everytime until now. When the Youtube publisher screen comes up you select a pic to go with it, and then upload to YouTube. The problem is that option is gone. I had to do a system restore because Sonar wouldn't open (some kind of error) I believe the app data got screwed up somehow. Anyway, after the restore I was on Everett and used command center to update to the latest. Everything seems to be fine except for this issue.

I have never tried it before. I have the option and it appears to work (at least it calls up the CakewalkYouTubePublisher). If you are not seeing the option I wonder if the registry entry is missing. Here is an export of the entry from my pc.
 
 
 
Windows Registry Editor Version 5.00

[HKEY_CLASSES_ROOT\CakewalkExtAudioEncoders\{C2F3B26C-4709-485E-B48E-575E5C1714B4}]
"Name"="YouTube Publish"
"Description"=""
"Path"="C:\\Program Files\\Cakewalk\\Shared Utilities\\YouTube Publisher"
"Extension"=".wav"
"CommandLine"="CakewalkYouTubePublisher.exe %I"
"InProcess"=dword:00000000
"KeepWaveFile"=dword:00000001
"ModalEncoder"=dword:00000001
"SourceFormat"=dword:00000000

I wonder how to fix this? Should I reinstall Sonar? I don't know how to even look in the registry.

To verify if the entry is there, run regedit, Edit > Find and search for youtube.
 
If the entry is not in the registry and if SONAR is in the default location on the C drive you could copy the registry part of my message above, paste it into a file with a .reg extension and execute the file. It will load the data into your registry.
 
If the entry is missing, I would wonder what else is missing though. If you are using C3 you could roll back to a previous versions and re-install.