bridge not displaying thumbnails -already tried purging cache

I view thumbnails of indesign files in bridge. Until yesterday, all of the files were displayed as thumbnails. Yesterday, after I clicked a thumbnail to open the file in indesign, it would change to the indesign file icon. I tried purging the cache which did nothing. I tried increasing the mb size of the allowed thumbnails and that did not work. I updated to the current versions of bridge and indesign. That did not change anything.