My solution if some previews in the KK browser are not available.

JorgeMCS

I have the newest Versions of Komplete * running on Windows 10.

After purchasing Ultimate 14 my disks ran out of space and so I moved 183 libraries to a new external HD (~800 GB). I needed several hours to do it.

After finishing the job some previews where not working. Komplete Kontrol tried to access the snapshots under the old path. I have reinstalled "Preview", "Komplete Kontrol" and "Kontakt" without any success.

After googeling for hours I found at least a hint to solve this issue (can't post the link here).

-------Cite Start:

NKS compatible libraries once installed show up in the Komplete Kontrol Browser. 

Occasionally, in rare cases these are not located correctly, one potential cause of this is if the samples have been moved after the initial install. 

First, open Native Access and ensure there are no updates for Komplete Kontrol. Install the latest update if available. Once update, remove the "favorites.db3" file.

1. Removing the Komplete.db3 file 

The "Komplete.db3" file will be located in the below locations. This will need to be done before deleting the favorites.db3 file.

Mac OS:

Macintosh HD > Users > Username > Library > Application Support > Native Instruments > Komplete Kontrol

Note: The User Library is a hidden folder on macOS. To access it, click Go in the Finder menu bar and press down the Alt key. The Library entry will now appear in the menu.

Windows:

C:/Users/[username]/AppData/Local/Native Instruments/Komplete Kontrol 

2. Removing the favorites.db3 file 

The "favorites.db3" file is located in the below locations. Upon reloading Komplete Kontrol the database will automatically update. 

Mac OS:

Mac HD > Users > Username > Library > Application Support > Native Instruments > Shared > 'favorites.db3'

Note: The User Library is a hidden folder on macOS. To access it, click Go in the Finder menu bar and press down the Alt key. The Library entry will now appear in the menu.

Windows:

C:/Users/[username]/AppData/Local/Native Instruments/Shared/favorites.db3

-----Cite end.

After deleting the db3 files I opened Komplete Kontrol and it rebuilt all instruments automatically. That took a long time in my case (did it over night).

Hint: do not forget to set the new destination path in the settings of NA.

Hint2: I do not know if the favorites are gone after this procedure (I don't work with it).

Kymeia

I would not recommend people deleting favorites.db3 except as an extreme last resort - many of us have spent a lot of time favouriting patches and you would lose the whole lot - I don't see how it has any relevance to previews anyway. Mostly previews being missing is a sign either they are not installed (eg some third party developers supply them separately) or in the wrong place, for they simply don't have them (as with some third party NKS that are not factory ones)

JorgeMCS

@Kymeia Thank you for your answer.

1.) Before I do such things, I rename every effected file or folder so I can turn back to the old config.

2.) When I use the function "relocate" then I expect a relocation of all parts for an instrument or extension. Everything worked before. "Phar-, Ash-, Staylight" for example have had no previews after relocation. I think this instruments are not third party.

3.) I have not found a function to manipulate the folder properties for previews in the existing NI software.

4.) My libraries where installed under different locations. That maybe caused the problem. With the new HD I have now all in one location.

5.) It is possible to modify the db3 database (I've knowledge of SQL) but not without a description of the database structure.