Batch re-save is a tool in Kontakt that can be beneficial for a couple of reasons:
1) If you're getting a "content missing" message on one of your libraries, despite being certain that the files are on your computer. (It also scans the library folder to check if you are unsure.)
2) You wish to speed up your sample loading times.
The Resave Process
1) With Kontakt open, locate the floppy disk and select Batch Resave from the dropdown menu.
2) You will receive a warning message, select Yes to proceed.
3) Select the folder for the library that you would like to re-save. For this example, I'll be performing the re-save on Masse.
Note: It is highly recommended to approach this one library at a time. Performing a re-save on multiple libraries will not only slow down the process, but can occasionally cause Kontakt to crash.
4) Kontakt will now begin to check your library. Once this is completed it's possible that you will see a "Content Missing" window.
If you do get this message, you can manually direct Kontakt to the location of the missing samples by selecting browse for folder, or allow Kontakt to search for the files automatically by selecting search filesystem.
If you do intend to resolve manually, you will need to know the location of the samples. For this example, I would manually select the Spitfire Masse library folder.
Note: If you have tried both methods and are still unable to locate the files, this could mean that you are missing the samples altogether. If this is the case, re-download the library and if the issue persists, contact support.
5) Kontakt will now perform the re-save. The speed of this will depend on the size of the library. Once this is complete, the window will automatically close indicating that the process is finished.