If you're like me and love to have everything organised perfectly before setting off on adventures (like preparing environments or going fishing), then you may have run into this issue when attempting to install your shiny new SharePoint 2013 instance.
Imagine if you will, a fresh new environment with Windows Server 2012 R2 and SQL Server 2014 and you, a fresh faced and enthusiastic employee who has been tasked with installing a brand new copy of SharePoint 2013 on it.
So you do your best to get everything sorted, your MSI's are all lined up and ready to go. You have gone ahead and made sure that all the Windows Updates are installed so you're on the front foot and not leaving any of the software open to vulnerabilities. You've also installed all of the SharePoint pre-requisites and followed all of the steps in your HPE Content Manager Installation Guide. You're ready to go, so you fire up Setup.exe from your SharePoint cd and then this...
AAAAARGH!!!! Ok, calm down. Breathe in, breathe out.
I'll just go check my Server Manager to see if its installed...
Ahhhhh, ok - so it IS installed. What the heck SharePoint! It's at this stage that I should tell you, do not, I repeat - DO NOT - uninstall 4.5 and try to reinstall. This will result in your servers GUI components being uninstalled as a part of the process and you'll be left with no server UI upon restart.
So who is to blame? Well, you've gone and gotten ahead of yourself. By installing the Windows Updates you have inadvertently installed Microsoft .Net 4.6 (or even 4.6.1) which has caused the SharePoint 2013 pre-requisite checker to fail.
Removing an update will result in the 4.6.x components to be removed, thus allowing you to proceed.
A big thanks to the community over at http://sharepoint.stackexchange.com/ for the fix here.
You can check out the full thread (and KB references for other OS's) here: