P: Lightroom: Ability to delete the default develop presets

Yes, hard-coded indeed.
I think the best real-world solution is to make a new Develop Presets folders and populate them with custom or imported presets. At least when LR is not running, those can be easily accessed as I described earlier, then re-organized into single-level deep folder structures. The Preset and Collections GUIs are showing their age, and will hopefully improve in the future.

Sorry David, it doesn't work for me. These things are hardcoded into LR.

On Mac, the names of the built-in preset folders that appear in the Presets panel  are hardwired (compiled) into LR ("Lightroom B&W Filter Presets", "Lightroom B&W Presets", etc.).   They can't be deleted without hacking LR compiled code. 

The .lrtemplate files themselves are stored in this Mac directory:

/Applications/Adobe Lightroom/Adobe Lightroom.app/Contents/PlugIns/Develop.lrmodule/Contents/Resources/templates/

You can delete the .lrtemplate files to prevent them from appearing in LR, but you can't delete the folders (which are hardwired, as described above).  If you try to delete the /templates folder, you'll get an error message on startup and none of LR's modules work.

I haven't investigated Windows for several years, but I'm pretty sure the situation is similar.

John,Thanks for making your video.  I can only surmise that Lightroom puts the default Presets folder somewhere else on that OX version, or for some reason adds it into the app package. I am running El Capitan on this Laptop, where it works on LRCC  2015.12 .  
Could they reside in a Lightroom Settings folder within the Pictures>Lightroom folder?That used to be one of Adobe's schemes in earlier versions.Sometimes a search for a default preset's name can reveal it's location, but newer OS is pretty opaque to searches once they reside outside of user-level folders. 
I'll be interested in seeing if you ever locate their whereabouts.
If I could edit my earlier replies, I'd clarify what OS I found this working on.Feel free to delete them if need be.

Unfortunately, your recipe doesn't work on my LR CC 2015.12 / OS X 10.12.6. Here's a screen recording showing that the Develop Presets folder doesn't contain the built-in presets, even though they appear in the Presets panel in Develop:  : https://www.dropbox.com/s/3qb5xrwvavwc2xr/Deleting-default-presets.2017.09.19.mov?dl=0

Ariel, My screen shots were made this morning on the current version of LRCC. I actually deleted the LR default presets to test it and rebooted.The ability to delete the default LR Develop presets does not appear version-dependent on my Mac, but I cannot speak for the same on a PC. 

This doesn't work on current Lightroom version, only on older versions.

Louis, see my reply to this thread below. It might help you.

It's very easy to delete Lightroom's default presets.

• Open Lightroom preferences (see illustration 1) Under Lightroom menu (Mac) or Edit menu (PC)
• Select the Presets tab along the top row. (see illustration 2)
• From there, click the "Show Lightroom Presets Folder" button at right. That opens the Presets folder within your drive's Library.
• Open only the DEVELOP Presets folder to reveal the default Lightroom Presets folder. Leave the User Presets folder alone.  (see illustration 3)
• 
  
• Now QUIT LIGHTROOM.
• Once your LR app has quit, you can safely delete the Lightroom Develop presets folder, or specific presets within it. Be sure to leave the User Presets folder there.
• REMEMBER, only re-installing Lightroom can bring back default presets, so its wise to back them up first.
• Once you have deleted any presets, close that window and you can re-launch Lightroom. The deleted Develop presets should be gone.
• NOTE: You can also use this method to quickly organize and group favorite presets into folders as I have as seen in the illustration. Be careful when naming folders and presets, use only alphanumeric characters. 
• A blank word space before the preset name or folder name will put it at the top of the list.
• NOTE: I have only done this on a MAC, so PC users could get different results. Let us know!
• Use caution whenever changing names or folders 'behind Lightroom's back'. Always save a backup of anything you alter this way, just in case. And ALWAYS operate with Lightroom not running.

Please Adobe, wake up on that. No one is needing these crappy presets after they've spent more than a month with LR. It cost nothing to you to let us being able to remove (even hide) them, this is using space on our busy screens...
Are you listening to your customers? It's not because you have the monopoly on that type of software that you can ignore us.
And honestly, it takes a couple of hours for a senior developer to do this...
Thank you.