I found that I was still missing 70+ updates after downloading updates with wsusofflineupdater so I manually downloaded them from the update catalog and added them in.
Powershell Script for slipstreaming updates (https://www.reddit.com/r/sysadmin/comments/4ak3h7/powershell_script_to_slipstream_windows_updates/)
cls
#This is the path to your latest DISM version. DISM 10 is required to slipstream Windows 10.
$DISMPath = "C:\Program Files (x86)\Windows Kits\10\Assessment and Deployment Kit\Deployment Tools\amd64\DISM\DISM.exe"
#This is any path that has enough hard disk space to mount the image and slipstream updates into it.
$MountPath = “D:\TempMount\mount”
#Update the paths below as necessary to point to your Windows Updates folders.
$UpdatesPath1 = "D:\WU\wsusoffline105\wsusoffline\client\w61-x64\glb\*"
$UpdatesPath2 = "D:\WU\wsusoffline105\wsusoffline\client\w63-x64\glb\*"
$UpdatesPath3 = "D:\WU\wsusoffline105\wsusoffline\client\w100-x64\glb\*"
#Update the paths below to point to your "install.wim" locations.
$WimFile1 = “D:\DeploymentShare\Operating Systems\Windows 7 x64\sources\install.wim”
$WimFile2 = “D:\DeploymentShare\Operating Systems\Windows 8.1 Enterprise x64\sources\install.wim”
$WimFile3 = “D:\DeploymentShare\Operating Systems\Windows 10 Enterprise x64 1511\sources\install.wim”
$WimFile4 = “D:\DeploymentShare\Operating Systems\Windows Server 2008 R2 x64\sources\install.wim”
$WimFile5 = “D:\DeploymentShare\Operating Systems\Windows Server 2012 R2 SERVERSTANDARDCORE x64\sources\install.wim”
Do {
#Cleanup any existing images that may already be mounted.
&$DISMPath /Cleanup-Wim
#Prompt user for choice of OS or to exit.
Write-Host ""
Write-Host "Windows Update Slipstream into Deployment Files"
Write-Host "1 - Windows 7 SP1 x64"
Write-Host "2 - Windows 8.1 x64"
Write-Host "3 - Windows 10 1511 x64"
Write-Host "4 - Windows Server 2008 R2 SP1"
Write-Host "5 - Windows Server 2012 R2"
Write-Host "0 - Exit"
$Choice = Read-Host -Prompt 'Select an Operating System to Update'
#Based on user's input above, update the variables to select the correct image and update file path.
If ($Choice -eq "1")
{
Write-Host "Please stand by, this can take a while depending on the number of updates."
Write-Host "Slipstreaming updates to Windows 7 SP1 x64..."
$WimFile = $WimFile1
$UpdatesPath = $UpdatesPath1
}
elseif ($Choice -eq "2")
{
Write-Host "Please stand by, this can take a while depending on the number of updates."
Write-Host "Slipstreaming updates to Windows 8.1 x64..."
$WimFile = $WimFile2
$UpdatesPath = $UpdatesPath2
}
elseif ($Choice -eq "3")
{
Write-Host "Please stand by, this can take a while depending on the number of updates."
Write-Host "Slipstreaming updates to Windows 10 1511 x64..."
$WimFile = $WimFile3
$UpdatesPath = $UpdatesPath3
}
elseif ($Choice -eq "4")
{
Write-Host "Please stand by, this can take a while depending on the number of updates."
Write-Host "Slipstreaming updates to Windows Server 2008 R2 SP1..."
$WimFile = $WimFile4
$UpdatesPath = $UpdatesPath1
}
elseif ($Choice -eq "5")
{
Write-Host "Please stand by, this can take a while depending on the number of updates."
Write-Host "Slipstreaming updates to Windows Server 2012 R2..."
$WimFile = $WimFile5
$UpdatesPath = $UpdatesPath2
}
elseif ($Choice -eq "0")
{
Write-Host "Exiting..."
break
}
#Mount the image in the temporyar mount path specified above.
&$DISMPath /Mount-Wim /WimFile:$WimFile /index:1 /Mountdir:$MountPath
#Apply the patches and show progress.
&$DISMPath /image:$MountPath /Add-Package /Packagepath:$UpdatesPath
Write-Host "Updates Applied to WIM, scroll up to check for any errors encountered."
#Commit changes to image that is currently mounted in the temporary mount path and write to disk.
&$DISMPath /Unmount-Wim /Mountdir:$MountPath /commit
#Clean up any mounted images.
&$DISMPath /Cleanup-Wim
}
#Return to the menu and wait on user input.
while ($Choice -ne "0")