Database error when making changes to DHCP reservations

“An error occurred while accessing the DHCP database.”

an error occurred while accessing the DHCP database

One of the issues I have ran into since an upgrade to Windows Server 2012 R2 DHCP servers – was due to multiple processes access the DHCP database when I was attempting to Create or Modify a DHCP v4 reservation.

  1. Adding an exclusion to DHCP.MDB file for Real Time scanning on my antivirus product.
  2. Disabling the Windows indexing service from indexing the DHCP folder.

To disable the Windows indexing service from indexing the DHCP server follow the quick steps below:

  1. Open Windows Explorer – or Computer: on the DHCP server
  2. Navigate to: c:\Windows\System32\DHCP
  3. Click on the General Tab up the top and click Advanced
  4. Uncheck ‘For Fast Searching, Allow Indexing Service to Index this Folder.’
  5. Click Ok

Useful Resources:

Microsoft Anti-Virus Exclusion List –

Enabling Disk Cleanup in Windows Server 2008 R2

In Server 2008 and Server 2008 R2, Disk Cleanup is Disabled by default. This is how you can enable disk cleanup in Windows Server 2008 R2 – 64bit.

You can enable the Desktop Experience role (which requires a restart to complete) but the easiest way is to copy the files from the WinSXS directory to the relevant directories – as mentioned below

OS File Location
Windows Server 2008 R2 C:\Windows\winsxs\amd64_microsoft-windows-cleanmgr_31bf3856ad364e35_6.1.7600.16385_none_c9392808773cd7da\cleanmgr.exe
Windows Server 2008 R2 C:\Windows\winsxs\amd64_microsoft-windows-cleanmgr.resources_31bf3856ad364e35_6.1.7600.16385_en-us_b9cb6194b257cc63\cleanmgr.exe.mui
  1. Copy Cleanmgr.exe to %systemroot%\System32
  2. Copy Cleanmgr.exe.mui to %systemroot%\System32\en-US
  3. Run Cleanmgr.exe from an elevated Command Prompt

How to install .NET Framework 3.5 on Windows Server 2012 and Windows Server 2012 R2

.NET Framework 3.5 needs the source files off the Windows Server 2012 DVD in order to install. You can do this online and without needing a restart using DISM.

1. Go to a command prompt and enter this:

dism /online /enable-feature /featurename:NetFX3 /all /Source:d:sourcessxs /LimitAccess

Note: Source should be the Windows DVD location, ie d: /Source:x if x is your DVD mount point.

How to disable Internet Explorer Enhanced Security in Windows Server 2012 R2

Note: This is not best practice and is not recommended to do in a production environment.

  1. Open Server Manager
  2. Click on Local Server (to the left)
  3. Select IE Enhanced Security Configuration
  4. Select Turn off and click Ok


Windows Server 2012 – This computer’s hardware may not support booting to this disk.

This usually occurs when you are using a new SATA or solid-state drive that hasn’t been initialized yet.

  1. To fix this issue – use the Windows Server 2012 device manager tools during setup to create the partition on the hard drive that you are attempting to install to. You can use this opportunity to layout any extra partitions that you may need.

Guide to using Hyper-V

Introduction to Hyper-V


Hyper-V is an emulation/hyper-visor Microsoft developed technology – similar to VMWare Workstation or ESXI that allows you to run Virtual Machines and different workloads simultaneously. Hyper-V is currently available in Windows 8, Windows Server 2008, Windows Server 2008 R2, Windows 8.1 & Windows Server 2012, Windows Server 2012 R2. The Hyper-V hypervisor allows multiple workloads to run on the same physical hardware that in the past would have otherwise only been suitable for one workload – allowing for power and resource efficiency.


Hyper-V Specifications


Host operating system:

To install the Hyper-V role, Windows Server 2008, Windows Server 2008 R2 Standard, Enterprise or Datacentre edition, Windows Server 2012 Standard or Datacentre edition, or Windows 8 (or 8.1) Pro or Enterprise edition is required. Hyper-V is only supported on x86-64 variants of Windows. It can be installed regardless of whether the installation is a full or core installation. Processor: An x86-64 processor

Hardware-assisted virtualization support: This is available in processors that include a virtualization option; specifically, Intel VT or AMD Virtualization (AMD-V, formerly code-named “Pacifica”).

A NX bit-compatible CPU must be available and Hardware Data Execution Prevention (DEP) must be enabled.

Although this is not an official requirement, Windows Server 2008 R2 and a CPU with second-level address translation support are recommended for workstations.

Second-level address translation is a mandatory requirement for Hyper-V in Windows 8


Minimum 2 GB. (Each virtual machine requires its own memory, and so realistically much more.)

Windows Server 2008 Standard (x64) Hyper-V full GUI or Core supports up to 31 GB of memory for running VMs, plus 1 GB for the Hyper-V parent OS.]

Maximum total memory per system for Windows Server 2008 R2 hosts: 32 GB (Standard) or 2 TB (Enterprise, Datacentre)

Maximum total memory per system for Windows Server 2012 hosts: 4 TB

Guest operating systems

Hyper-V in Windows Server 2008 and 2008 R2 supports virtual machines with up to 4 processors each (1, 2, or 4 processors depending on guest OS-see below)

Hyper-V in Windows Server 2012 supports virtual machines with up to 64 processors each.

Hyper-V in Windows Server 2008 and 2008 R2 supports up to 384 VMs per system.

Hyper-V in Windows Server 2012 supports up to 1024 active virtual machines per system.

Hyper-V supports both 32-bit (x86) and 64-bit (x64) guest VMs.


Improvements of Hyper-V in Windows Server 2012


Hyper-V Extensible Virtual Switch

Network virtualization


Storage Resource Pools

.vhdx disk format supporting virtual hard disks as large as 64 TB with power failure resiliency

Virtual Fibre Channel

Offloaded data transfer

Hyper-V replica

Cross-premise connectivity

Cloud backup


Installing Hyper-V in Windows 8 & Windows 8.1


  1. Navigate to Control Panel & select Uninstall a Program underneath programs
  2. Select Turn Windows Features On or Off
  3. Check Hyper-V & Hyper-V Platform and select additional relevant features – I would HIGHLY recommend Hyper-V GUI Management Tools.
  4. Windows will go through and install the Hyper-V modules onto the Windows 8 workstation. Once completed the workstation will need a restart and you will be able to now fully utilise Hyper-V!


Installing Hyper-V for Windows Server 2012


  1. Open Server Manager
  2. Click Add Roles and Features and click Next
  3. Select Hyper-V Role and click Next
  4. Select the appropriate NIC (network interface card) for live migration and select Next
  5. Select the default locations for your VHD (virtual hard disks) and VM (virtual machine) configuration files to be held and select Next
  6. Once the Hyper-V role has been fully installed – restart the Windows Server 2012 machine. You should now have access to the Hyper-V Manager.


Hyper-V Tips and Tricks


How to stop and restart the Hyper-V service


  1. Open Hyper-V Manager
  2. Select the relevant Hyper-V server
  3. Select Stop Service


How to create a new Virtual Machine in Hyper-V


  1. Open Hyper-V Manager
  2. Select New and Virtual Machine
  3. The before you Begin Wizard will now appear – click Next
  4. Choose a name for your Virtual Machine and verify the storage location is for the virtual machine is appropriate and click Next
  5. Here you can select the “generation” of the Virtual Machine.
  6. Generation 1 – These are for 32bit legacy based systems usually used for Windows 7 and Windows XP/Linux virtual machines.
  7. Generation 2 – These are for Windows Server 2012 or 64bit versions of Windows 8
  8. NOTE: Once Virtual Machine generation has been selected – YOU CANNOT change it.
  9. NOTE: Using Convert-VMGeneration script you can convert a Generation 1 VM to Generation 2.
  10. You can now select the RAM amount you would like to delegate to your Virtual Machine and select Next
  11. If you have VLAN setup you can set your Virtual Machine to use the connection – I don’t so I am just going to click Next
  12. Now you can specify the appropriate VHD (Virtual Hard Disk) for the Virtual Machine to use – you can either create a new one or use an existing VHD.
  13. This is where you specify the path to your installation media for your virtual machine – such as an OS (operating system) ISO.
  14. You have finally setup your new Virtual Machine! Verify all the settings are correct and click Finish to configure and generate your new Virtual Machines.
  15. You can now right click on your Virtual Machine under the Hyper-V Manager and select Connect… to start it.

Windows Server 2012 – Convert Core installation to full GUI installation

  1. You have to have administration rights for this – open an elevated powershell prompt and type: Install-WindowsFeature Server-Gui-Mgmt-Infra, Server-Gui-Shell –Restart press Enter for the cmdlet to install the Server 2012 user interface.

How to adjust the Server Manager Refresh rate in Windows Server 2012

  1. Open Server Manager
  2. Click Manage (top right)
  3. Click Server Manager Properties
  4. Make sure “Specify the Server Manager Data refresh period (in minutes)” is ticked
  5. Type in the number of minutes you want to refresh your server(s) status.
  6. Click Ok