I cannot see my .eps and .ai thumbnails as an image in Bridge. I know the ability is there because when I had the creative cloud before it worked. I have reset the preferences at startup. Cleared the cache as well. I have also went into edit preferences in Bridge to "do not process files larger than" and increased the amount. Doesn't work. Nothing seems to work. I have a big library of vector art that I was always able to view in Bridge. Does anyone have a fix?
Any time there is a change like you describe, either the application has changed or your computer has changed.
For the application there might been a change in the application with an update or there could be something amiss on the computer such as a screwup with the Preferences (requiring a resetting of the Preferences such as you've already done).
For the computer there could be issue that your computer is too old to use the features or your software OR new and your old preferences are no longer valid on the new computer. Alternativley you've updated your OS or your computer needs some general (digital) maintenance.
But, as you say, it should work. To help I need a tad more information:
What is your OS (and what release)?
What version of Adobe software are you using (and what release)?