The installation of LibreOffice on Windows systems in my laboratory (University of Calabria, Italy) caused the immediate abandon of the program for 5 out of 6 new users. This is the only reason why I am reporting these as major bugs.

The reason for immediate abandon is the fact that LibreOffice behaves in a non-standard way with respect to the rest of all the other programs for Windows. 

Here the details:

1. The programs leaves a 222 Mb file called "LibreOffice 3.3 (4d80c175) Installation Files" in the same directory where the Installer program (of similar size) was (on the Desktop, in our case). Some users didn't know what to do with this file, didn't dare to erase it because it was unclear to them if needed in the future, and didn't dare to move it in fear of breaking functionalities. Since no other program does the same at installation, some users concluded that something was wrong either with the installation or with the program itself. Thus, they uninstalled it.  

2. In Windows, when you install a program able to manage a .xyz file, that program is automatically listed among the programs able to open those files, and you can recall the program with (a) right click of the mouse, (b) menu entry "Open with", (c) if needed - selecting among "Predefined programs". Trying to open a .doc file, LibreOffice Writer was not listed. Finding it required browsing among directories in search of the swriter.exe file, something that no other program requires and that is not trivial for a dumb Windows user. Especially since you *don't know* that the file is called swriter.exe rather than librewriter.exe, writer.exe, xwriter.exe of whatever.exe. Some users simply gave up in fear of having to repeat the same for .rtf, .docx, .xls, .ppt, and zillions of other extentions.

Sorry guys, you are doing a tremendous good job but what you lost users for trivial usability issues. Either you are doing it wrong or the rest of the world, because no other programs behave this way. 

Thanks for your attention, 
Bruno.