I have downloaded and installed the latest version of Libre (6.0.1.1) and at the same time downloaded the help files. The installation of Help proceeded as I would expect and was stated to be successful, but when I try to use help I get the message that it is not installed. I have tried to re-install it but have to click Repair, so it must be installed.
(Speaking of Window as OS: The downloaded file is an .msi file (MicroSoft Installer). It must be installed itself befor the offline help actually is availabe. Start the process by doubleclicking the installer file and the installation should run. )
Please also note that the helpfile language must match the UI language.
Did you choose a different folder to install LibO in?
Find the folder containing the soffice.exe of your installed LibO. Its name should be program. The folder containing this program folder should alo contain a folder named help. This help folder will contain one or more subfolders named by laguage abbreviations (mostly 2 letters) and probably followed by a dash and a country abbreviation. This ab-xy must match your UI language semantically. (You may find a gb instd of UK or something like that.) If all this is as it should be but doesn’t work, I only can think of a version mismatch. Please report exactly and completely the filenames of the installers used for the LibO and for the help, and the exact name of the UI language as shown in the Options dialog in this case.
(Edit regarding the other “answer”
You (the OQ) still din’t report the UI-language.
If you are definitely sure there cannot be any kind of mismatch (precise version, bit-width, precise UI-language) you may next try a reset user profile as a possible rescue, See this wiki page. Bee careful.
A folder c:\programfiles\libreoffice\program contains a folder libreoffice, which contains a folder help, which contains a folder en-GB – there is a file soffice.exe in that folder. The en-GB folder is 24.4Mb.
The libre office program is version 6.0.1.1 (x64), the download help pack installer file is version 6.0.1 help pack.en-GB.msi
The computer is an x64 with Windows 10 fall creators upgrade with the latest patches.
The message I get is “The LibreOffice built-in help is not installed on your computer.”
Later. I have removed both the Help and the main Libre program, downloaded the latest 6.0.2 versions of each and re-installed. Unfortunately the result is the same.
(This is not a answer. Better edit the question to give additional info.)
-1- You still did not tell the (exact) UI-language.
-2- You still did not tell the exact names of the msi-files. (Background: there might be a problem with the bit-width. The help\en-GB folder might the contain an older version while the new one was installed to another relic in the x86 range.)
-3- I would probably try a completely new installition looking for the results after every step very thoroughly