as I recall, the default production output folder is the Camtasia folder; but you can set a different destination by doing a custom production; that destination should then be remembered until changed again [at least this is how it works when producing to MP4 w/controller
On the last production option window, you can set your folder to where you want. That setting should "stick" until you change it to something else. If you have changed the location a few times, You should be able to select your location using the drop-down menu in the location field.
Changing the registry was the only way I could ever tame this beast. :( Here is how it looked in CS8. You should verify in C9 and test by allowing C9 to make changes; comparing the before and after before making any changes. I strongly suggest saving any key before manually changing any value or data. Don't touch the registry if you don't know what you are doing or are unwilling to cause damage to your system. Do not add any entries or change anything but the data.
HKEY_CURRENT_USER\Software\TechSmith\Camtasia Studio\8.0\Camtasia Studio\8.0
Data: (fully qualified folder path followed by an asterisk)
My notes also mentioned this entry
Key: same as above
ProductionFolderMru is easily understood. I'm not sure about CreateProductionFolder.