现在的Server用Windows Server 2012 R2的越来越多了，在部署带Sp1的SharePoint2013的时候，走完预安装工具后，点击setup提示缺少。net4.5。
其实Windows Server 2012 R2打完所有更新补丁后，操作系统的.net版本已经是4.6.1了，因为。net4.6是os的组件的一部分，所以无法直接卸载，也不能单独去手工安装。net4.5安装包。
通过dotnetfx_cleanup_tool 卸载失败了。
2种解决办法：
a. 修改注册表：
1.Run regedt32 as administrator (best method is to browse to system32 directory and right click)
2.Browse to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v43.Export the key (and all subs) for safekeeping •Especially import to get these 2 keys that you will be editing
•HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Client
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full
4.Right click on v4 and choose Permissions •Click Advanced
•If the owner is listed as System you may have to change to the local administrator group (or account you using to edit the registry) and choose “Replace Owner on subcontainers and objects”.
5.Right click on Client key and choose Permissions. Grant your group/account full control.
6.Make note of the value for the version entry – keep it somewhere safe.
7.Change the value to 4.5.50709 – minimum version required for SharePoint 2013. You can use this version or another valid version above that but not any 4.6 values.
8.Right click on Full key and choose Permissions. Grant your group/account full control.
9.Make note of the value for the version entry – keep it somewhere safe.
10.Change the value to 4.5.50709
11.Run SharePoint install.
12.When the install is finished, before running config wizard, you can either run the reg file you created in Step 3 or manually set the version values back to the value as noted in Step 9.
13.If you changed the owner as outlined in step 4, be sure to set it back to System and choose “Replace Owner on subcontainers and objects”.
b. 更新安装补丁：
找到你安装的软件版本，选择下面一个补丁文件到本地
•SharePoint Foundation 2013 with Service Pack 1 fix
https://download.microsoft.com/download/3/6/2/362C4A9C-4AFE-425E-825F-369D34D64F4E/wsssetup_15-0-4709-1000_x64.zip
•SharePoint Server 2013 with Service Pack 1 fix
https://download.microsoft.com/download/3/6/2/362C4A9C-4AFE-425E-825F-369D34D64F4E/svrsetup_15-0-4709-1000_x64.zip
•Project Server 2013 with Service Pack 1 fix
https://download.microsoft.com/download/3/6/2/362C4A9C-4AFE-425E-825F-369D34D64F4E/svrsetup_15-0-4709-1000_x64.zip
拷贝解压缩的dll到SharePoint 2013 ios或者img解开后的updates文件夹中，再次启动setup安装，通过了。
推荐方案b。