When I installed the new version of LibreOffice on my Windows 8.1 desktop, it will pop up during the validating install process stating that you have to close explorer.exe to continue. If you tell it to ignore it, it will not proceed until you close it. I had to go to task manager and kill explorer.exe to finish installing. Then, you have to re-launch explorer.exe to be able to use anything in windows 8.1 .
What was your previous version?
*** This bug has been marked as a duplicate of bug 69066 ***