LibreOffice 5.2.5 fails to install

How do I install LibreOffice version 5.x?
Running Windows 10 Pro version 1607
Have LibreOffice 4.4.7.2
Downloaded LibreOffice_5.2.5_Win_x86.msi
As soon as it has checked for space I am given access to a"Nästa" (“Next”) button
I click it and leave “Typiskt” (Typical) checked
I leave the default (Create icon on the desktop) checked and click “Installera” (Install)
I am greeted with a splash translated by me as: (The installation guide is complete.
The installation was aborted before LibreOffice 5.2.5.1 was finished
the system has not been changed
You can run the installation later to complete the installation
Click to close the guide)
That’s it! I cannot install this version!
Couldn’t install the previous 5.X that I attempted a few weeks ago either!
I cannot remove LibreOffice 4.4.7.2 through the Control Panel to try with no LibreOffice installation.

I cannot remove LibreOffice 4.4.7.2 through the Control Panel to try with no LibreOffice installation

I suppose that this is actual problem that you have. When LO is installed, it looks for an older version and, if found, uninstalls it before installing itself. If it fails uninstalling, it cannot proceed.

Possibly you have your Windows installation database corrupt. It may happen e.g. when some “useful registry cleaners” are used (my advise would be to never use such kind of software), or from other OS failures (e.g. failures when installing any program could cause that).

My following advise is quite dangerous, so only try to follow it if you are experienced user, and don’t forget to backup first. I tried that before, and it always gave me good results, but YMMV, and the utility I’m talking about may be used wrong and create more havoc.

You may use a utility from MS called “Windows Installer CleanUp Utility”, that used to be available from their site to fix MS Office installation problems. However, it is no more available there, so you may need to search web archives for a copy. If you start it, you will find a list of installed programs OS knows of. You need to look for your LibreOffice entry there, and delete information about it (remember not to remove everything!) This procedure doesn’t remove installed LibreOffice itself; it just makes Windows Installer to forget that the program was installed. So, following installation would not find previous version, and complete successfully.

Given LO installation procedure, this is quite safe if you do it properly. It by no means isn’t a universal advise, and should not be used to fix any problem with any software. But LO in essence just copies itself to program directory, installs some fonts, and registers some file associations, and next version effectively repeats it, so ~no garbage would result.