Problem Importing Develop Presets

I came to the same concluion. LR cannot import a preset that is already installed. When a preset is deleted, LR does not always get the message that the deleted preset is no longer present, and therefore won't let it be reinstalled.      

"but no luck."

Does this mean you are still not successful, or has my 'correct answer' worked for you?

My accumulation of Presets are all stored in my {Documents} folders (both purchased and own created) , where they will be always backed up with other documents. And I save new ones there, and Import them from there when or if needed.

This is my 'saved' files-{D:\Data\Documents\Photographic Lightroom\Presets for Lightroom\Local Adjustment Presets}

And to Import any Presets from {Documents} my procedure is-

1) Click the [+] Choose [Import Presets...]

2) Locate and select the Preset files (in my 'saved' locations)

3) Click the [Import] button

Boom! Done!

The 'Import Presets' Process may NOT place the Presets in Groups that 'mirror' the Folders on the Hard-drive, and the Presets may NOT bear the same Name in the Presets panel as the Filenames on the Hard-drive!

Search for installed Presets in all Groups (often in 'User') and expand Groups with the 'spinner triangle' on each Group.

.XMP Presets may also be 'Profile' presets- they will install in the Profile Browser panels.

Thank you Wobert for the links which I will review.  I have already tried your suggestion for importing but no luck.  Cheers.