LibreOffice installer for Windows (MSI) writes to these locations (drive
C: is assumed the system drive below):
- Most files go to install location - that is
C:\Program Files\LibreOffice by default, and is customizable on Custom Setup step of installation wizard.
- Fonts: about 70 MB goes to
- System components used by LibreOffice: installer runs MSU for UCRT and merge module for MSVC - in total, about 3 MB files go to
C:\Windows\System32 (if not yet present).
That’s all that MSI does. Now there is also one thing that Windows Installer service does itself for own needs: it caches the MSI into
C:\Windows\Installer hidden folder. Given the size of LibreOffice MSI, it takes ~300 MB.
So for installation on another drive, it would be normal for install process to take size of installer plus slightly more than 70 MB on system drive after the installation finishes. That is confirmed by direct measurement I did when testing this on a dedicated clean VM with Win7SP1 and 2 virtual disks: took “space used on drive” before and after installation, and also before and after removal.
The different thing is what installer tells in “Disk Space Requirements” dialog. And that indeed shows it needs almost 600 MB space on system drive when installing on another drive. But that number doesn’t mean that it will actually take all that space after installation finishes: it’s just the free space needed in the process of installation (e.g., for temporary files created in
Temp directory; for undo information kept while installing to enable rollback on installation error in hidden
C:\Config.Msi, etc.), which is cleared at the end of the process. So that number indicates the space without which installation cannot proceed successfully.
By the way, removal of that cached MSI from Windows\Installer is not a good idea, because it would make clean uninstallation of programs impossible without the original MSI at hand.