Poison Library

invalid library found in C:\USERS\bjwat\Documents\Arduino \libraries\h.Si5351 etc
how do i get rid of this problem please
seems like I have to many Sketches with Si5351 programming and I cant load any of them

Do not hijack. Thread split.

That library is installed incorrectly (empty folder? library inside a folder inside that folder?), delete that folder and, if you don't also have a working copy of that library installed correctly, reinstall it, being sure to follow the installation instructions. The name of the folder should match the library name (without the .h) and that folder should contain some files (including a library.properties file) and an src folder containing the library itself and examples folder containing the example code; neither the library.properties nor the src and examples folder can be in another folder inside the library folder.

You should be able to use library manager to automatically install the library (see readme) if that's the library I think it is.