How to Change a Computer’s Mac Address in Windows with Screenshots

Source : wiki

There might be a time when you want to change the MAC address of your network adapter. The MAC address (Media Access Control address) is a unique identifier which is used to identify your computer in a network. Changing it can help you diagnose network issues, or just have a little fun with a silly name. See Step 1 below to learn how to change the MAC address of your network adapter in Windows.

Method 1

Device Manager

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    1

    Open the Device Manager. You can access the Device Manager from the Control Panel. It will be located in the System and Security section if you are using Category View.

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    2

    Expand the Network Adapters section. In your Device Manager, you will see a list of all of the hardware installed on your computer. These are sorted into categories. Expand the Network Adapters section to see all of your installed network adapters.

    • If you are not sure which adapter you are using, see Step 1 at the beginning of this article to find your device’s Description.
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    3

    Right-click on your adapter. Select Properties from the menu to open the network adapter’s Properties window.
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    4

    Click the Advanced tab. Look for the “Network Address” or “Locally Administered Address” entry. Highlight it and you will see a “Value” field on the right. Click the radio button to enable the “Value” field.

    • Not all adapters can be changed this way. If you can’t find either of these entries, you will need to use one of the other methods in this article.
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    5

    Enter your new MAC address. MAC addresses are 12-digit values, and should be entered without any dashes or colons. For example, if you want to make the MAC address “2A:1B:4C:3D:6E:5F”, you would enter “2A1B4C3D6E5F”.
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    6

    Reboot your computer to enable the changes. You can also disable and re-enable your adapter within Windows for the change to become effective without rebooting. Just sliding the Wi-Fi’s On/Off switch like the slider found on ThinkPads and VaiOs won’t satisfactorily disable/re-enable the card.
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    7

    Check that the changes took effect. Once you’ve rebooted the computer, open the Command Prompt and enter ipconfig /all and note the Physical Address of your adapter. It should be your new MAC address.

Method 2

Registry Editor

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    1

    Find your network adapter’s ID information. In order to easily identify your network adapter in the Windows Registry, you’ll want to gather some basic information about it through the Command Prompt. You can open the Command Prompt by typing “cmd” into the Run box (Windows key + R).

    • Type ipconfig /all and press Enter. Note the Description and Physical Address for the active network device. Ignore devices that aren’t active (Media Disconnected).
    • Type net config rdr and press Enter. Note the GUID, which is displayed between the “{}” brackets next to the Physical Address you recorded earlier.
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    2

    Open the Registry Editor. You can start the Registry Editor by opening the Run dialog box (Windows key + R) and typing “regedit”. This will open the Registry Editor, which will allow you to change the settings for your network card.

    • Making incorrect changes to the registry can cause your system to malfunction.
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    3

    Navigate to the registry key. Go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E972-E325-11CE-BFC1-08002BE10318}. Expand it by clicking the arrow.
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    4

    Find your adapter. There will be several folders labeled “0000”, “0001”, etc. Open each of these and compare the DriverDesc field to the Description you noted in the first step. To be completely sure, check the NetCfgInstanceID field and match it with the GUID from the first step.
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    5

    Right-click on the folder that matches your device. For example, if the “0001” folder matches your device, right-click on the folder. Select New → String Value. Name the new value “NetworkAddress”.
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    6

    Double-click the new Network Address entry. In the “Value data” field, enter your new MAC address. MAC addresses are 12-digit values, and should be entered without any dashes or colons. For example, if you want to make the MAC address “2A:1B:4C:3D:6E:5F”, you would enter “2A1B4C3D6E5F”..
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    7

    Ensure that the MAC address is formatted properly. Some adapters (especially Wi-Fi cards) are unforgiving of MAC addresses changes if the first octet’s 2nd half isn’t a 2,6,A,E or begins with a zero. This requirement has been observed as far back as Windows XP and is formatted as:

    • D2XXXXXXXXXX
    • D6XXXXXXXXXX
    • DAXXXXXXXXXX
    • DEXXXXXXXXXX
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    8

    Reboot your computer to enable the changes. You can also disable and re-enable your adapter within Windows for the change to become effective without rebooting. Just sliding the Wi-Fi’s On/Off switch like the slider found on ThinkPads and VaiOs won’t satisfactorily disable/re-enable the card.
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    9

    Check that the changes took effect. Once you’ve rebooted the computer, open the Command Prompt and enter ipconfig /all and note the Physical Address of your adapter. It should be your new MAC address.[1]

Firefox – Error code: sec_error_reused_issuer_and_serial

 
Most likely it is due to a conflict in self signed certificate that you added as exception in Firefox.

Close Firefox & delete C:\Documents and Settings\<userAccount>\Application Data\Mozilla\Firefox\Profiles\<userProfile>\xxxxx. This will basically remove all the exceptions that you have added earlier.

Note: At times I had to delete the cert_override.txt file too from the same folder to get things working.

Open Firefox again, you should be good

How to Disable “Internet Explorer Enhanced Security Configuration” on your Windows Instance

NOTE: Please read the information on this feature on Microsoft Technet before proceeding so you understand what this feature does and what disabling it can do: Technet article on Internet Explorer Enhanced Security Configuration

1. Open up Server Manager. It should open by default when you access your instance, but if not you can pull this up by going to your Start button -> All Programs -> Administrative Tools -> Server Manager

2. Once in the Server Manager you will see under the Security Information an option for Configure IE ESC:

3. You can choose to Enable/Disable it for just the Administrator account or for all User accounts: