I had this issue and this is how I solved it on Ubuntu 18.04.1 (in principal it should work with any Linux version):
First make sure you have LibreOffice and Mendeley installed. In my case I installed Mendeley through their .deb
file and LibreOffice through Snap. The following line will search for libreoffice in the installed snaps on your computer and if it finds anything it will show it:
snap list | grep -i libreoffice
This is what you get:
libreoffice 6.1.0.3 80 stable canonical✓ -
Then you need to know where Mendeley is storing the OpenOffice plugin. so let's search for it:
sudo find / -name "openOfficePlugin"
This is what I got:
/opt/mendeleydesktop/share/mendeleydesktop/openOfficePlugin
Remember that /opt/
is not readable without sudo
.
Now you can copy the openOfficePlugin folder to somewhere that is readable by LibreOffice:
cp -r "/opt/mendeleydesktop/share/mendeleydesktop/openOfficePlugin" "~/Downloads"
Now you have to open the "LibreOffice Writer" and "Mendeley" applications.
From the LibreOffice Writer menu, go to "Tools" > "Extension Manager..." (alternatively in version 6.1.0.3 you can use Ctrl+Alt+E to open the Extension Manager)

Now using the "Add" button, go to the ~/Downloads/openOfficePlugin
and open the file (in my case it is Mendeley-1.19.2.oxt
but the version might be different in your case).
It takes about a second to add the plugin and then after restarting your LibreOffice, you have the Mendeley toolbar in LibreOffice Writer. If you have your Mendeley open it should automatically connect to it and you can access your library.
