Bizarre, because I THINK what has happened is this. See my picture below.It is my CC3 desktop view and note there is no Symbol Catalog. At the bottom right of the screen, you will see a button with what looks like a HAMMER in it. CLicking this brings up the menus shown in the middle of the screen (Shown in my image). Note that the SYMBOL CATALOG in my example is NOT selected. The little box is empty. Click the box so a Check Mark appears and then select OK and the Symbol Catalog will reappear.
Let me know if this did not work.
Also, make sure you have upgraded to the most current version, would save you the need to reinstall. SHould be CC3 Version 3.40