I recently upgraded to LR CC and all of my presets that I had created over the years have disappear - I cannot find them anywhere at all - I've uninstalled LR5 and there are other that are still there, just not the ones I made?
Check to see if you have your presets "saved with the catalog". If yes, try turning that off.
(LR6 upgraded your lr5 catalog to a new LR6 formatted catalog.)
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