Quote from https://zhidao.baidu.com/question/585739776.html
LLB file in the LabVIEW library files
Typically, when the need to create a file, we naturally think of to select the menu "File-> New". However, in LabVIEW 8, the "New" menu LLB not see this type of file; you want to create or manage a LLB file, first select "Tool-> LLB Manager ...". After opening the LLB Manager, select the menu "File -> New LLB". So as to create a new LLB file out.
I personally believe in and later LabVIEW8 in, LLB file is now no longer necessary, and use it more harm than good. LLB file function is a group of VI and other relevant documents packaged stored together. The advantage is to save disk space, LLB file is compressed. However, in recent years, the capacity of the rapid expansion of computer storage media. LabVIEW storage space program is no longer a need to consider the issue. So this is no longer tempting. LLB file has many drawbacks. Internal documents no hierarchy, all the files are stored in the same level. As a result, documents and more, it can not be seen directly call their relationship. In addition, LLB also allows the same name file exists. Internal file name length restrictions, it probably limit the dozens of characters, the file name is too long will be automatically cut off. It is not conducive to version management. LLB in a file is modified, the entire LLB also been modified. In this way, one can not make incremental storage, the second is not easy to locate specific files had been altered.
Summing up the appeal, if the new project, it is best not to consider the use of LLB files. Meanwhile, in order to facilitate the project file management, you should try to take advantage of new features in LabVIEW 8: Project and Library.