SCCM Reboot DECODED:: How to make a PC Cancel, Start, Extend or Change mandatory reboot to non-mandatory on the fly.

SCCM Reboot DECODED:: How to make a PC Cancel, Start, Extend or Change mandatory reboot to non-mandatory on the fly.

In the past to stop a PC from rebooting when you didn’t want it to people would stop the ccmexec service and do a shutdown /a

But here is the problem with that..

1.  Shutdown /a will normally tell you that no shutdown is pending.
2.  Any number of things can restart ccmexec.

First, how to check if a reboot is pending VS a reboot is GOING to happen

On a win10 PC or has powershell 5 installed, use this

#Detect pending reboot:
Invoke-CimMethod -Namespace root/ccm/ClientSDK -ClassName CCM_ClientUtilities -MethodName DetermineIfRebootPending

On a win7 or old powershell 2 you need to use these.

#
([wmiclass]'ROOTccmClientSDK:CCM_ClientUtilities').DetermineIfRebootPending().RebootPending
([wmiclass]'ROOTccmClientSDK:CCM_ClientUtilities').DetermineIfRebootPending().IsHardRebootPending
([wmiclass]'ROOTccmClientSDK:CCM_ClientUtilities').DetermineIfRebootPending().RebootDeadline
([wmiclass]'ROOTccmClientSDK:CCM_ClientUtilities').DetermineIfRebootPending().NotifyUI

It will spit out something like this..

#PC with no pending reboot.

DisableHideTime     : 12/31/1969 2:00:00 PM
InGracePeriod       : False
IsHardRebootPending : False
NotifyUI            : False
RebootDeadline      : 12/31/1969 2:00:00 PM
RebootPending       : False
ReturnValue         : 0
PSComputerName      :

#PC with pending NON-mandatory reboot.

DisableHideTime : 12/31/1969 12:00:00 PM
InGracePeriod : False
IsHardRebootPending : False
NotifyUI : True
RebootDeadline : 12/31/1969 12:00:00 PM
RebootPending : True
ReturnValue : 0
PSComputerName :

#PC with pending mandatory reboot, notice the time stamp.

DisableHideTime : 5/1/2019 3:28:56 PM
InGracePeriod : True
IsHardRebootPending : False
NotifyUI : True
RebootDeadline : 5/1/2019 11:28:56 PM
RebootPending : True
ReturnValue : 0
PSComputerName :

Now for the magic…..

Everything that SCCM uses for knowing when and if it should reboot comes from here.

HKLM:\SOFTWARE\Microsoft\SMS\Mobile Client\Reboot Management\RebootData

On a PC with no reboot pending, this key is empty.

So starting with that, this is how we can CANCEL a pending reboot.

#CANCEL a pending reboot
Remove-Item -path 'HKLM:\SOFTWARE\Microsoft\SMS\Mobile Client\Reboot Management\RebootData';
Remove-Item -path 'HKLM:\SOFTWARE\Microsoft\SMS\Mobile Client\Updates Management\Handler\UpdatesRebootStatus\*';
Remove-ItemProperty -name * -path 'HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update\RebootRequired';
#on PS2.0, "Remove-ItemProperty" doesn't work, so use this.
#Remove-Item -path 'HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update\RebootRequired';
shutdown -a 
Restart-Service ccmexec -force

But what if you just want to cancel the mandatory reboot and change it to a non-mandatory reboot so the user will still get the popup telling them they “need to” reboot?

#change mandatory reboot to  non-mandatory reboot
Set-Itemproperty -path 'HKLM:\SOFTWARE\Microsoft\SMS\Mobile Client\Reboot Management\RebootData' -name 'RebootBy' -value 0;
Restart-Service ccmexec -force

What if we just want to extend the time of a mandatory reboot?

Example: In your client settings you have your reboot countdown set to 10 hours…. A user calls and says it’s going to reboot in 10 min and needs it extended… This will reset that users countdown timer back to 10 hours.

#Reset SCCM reboot countdown timer.
$time = [DateTimeOffset]::Now.ToUnixTimeSeconds()
Set-Itemproperty -path 'HKLM:\SOFTWARE\Microsoft\SMS\Mobile Client\Reboot Management\RebootData' -name 'RebootBy' -value $time;
Restart-Service ccmexec -force

What if you want to kick off the built in SCCM reboot WITH the client settings countdown timer?
NOTE: Setting $Time to 0 will popup the non-mandatory reboot window.

$time = [DateTimeOffset]::Now.ToUnixTimeSeconds()
New-ItemProperty -LiteralPath 'HKLM:\SOFTWARE\Microsoft\SMS\Mobile Client\Reboot Management\RebootData' -Name 'RebootBy' -Value $time -PropertyType QWord -Force -ea SilentlyContinue;
New-ItemProperty -LiteralPath 'HKLM:\SOFTWARE\Microsoft\SMS\Mobile Client\Reboot Management\RebootData' -Name 'RebootValueInUTC' -Value 1 -PropertyType DWord -Force -ea SilentlyContinue;
New-ItemProperty -LiteralPath 'HKLM:\SOFTWARE\Microsoft\SMS\Mobile Client\Reboot Management\RebootData' -Name 'NotifyUI' -Value 1 -PropertyType DWord -Force -ea SilentlyContinue;
New-ItemProperty -LiteralPath 'HKLM:\SOFTWARE\Microsoft\SMS\Mobile Client\Reboot Management\RebootData' -Name 'HardReboot' -Value 0 -PropertyType DWord -Force -ea SilentlyContinue;
New-ItemProperty -LiteralPath 'HKLM:\SOFTWARE\Microsoft\SMS\Mobile Client\Reboot Management\RebootData' -Name 'OverrideRebootWindowTime' -Value 0 -PropertyType QWord -Force -ea SilentlyContinue;
New-ItemProperty -LiteralPath 'HKLM:\SOFTWARE\Microsoft\SMS\Mobile Client\Reboot Management\RebootData' -Name 'OverrideRebootWindow' -Value 0 -PropertyType DWord -Force -ea SilentlyContinue;
New-ItemProperty -LiteralPath 'HKLM:\SOFTWARE\Microsoft\SMS\Mobile Client\Reboot Management\RebootData' -Name 'PreferredRebootWindowTypes' -Value @("4") -PropertyType MultiString -Force -ea SilentlyContinue;
New-ItemProperty -LiteralPath 'HKLM:\SOFTWARE\Microsoft\SMS\Mobile Client\Reboot Management\RebootData' -Name 'GraceSeconds' -Value 0 -PropertyType DWord -Force -ea SilentlyContinue;

NOTE:: In all my tests after you run The powerShell command it takes about 30 seconds for the client to respond since after you restart the service it has to do all it’s internal checks to figure out what’s new.

#WeaponizedAutismFTW

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