Step 1: Access Microsoft Management Console (MMC)
From the Start screen, type Run and click enter. In the Run window, type mmc and then, click Ok. If the User Account Control window appears, click Yes to allow MMC to make changes.
Step 2: Add Certificates to selected Snap-ins
In the Console window, click File > Add/Remove Snap-in.
In the Add or Remove Snap-ins window, under Available snap-ins, click Certificates and then click the Add button.
In the Certificates snap-in window, click Computer account and then click the Next button.
In the Select Computer window, click Local computer: (the computer this console is running on) and then click the Finish button.
Step 3: Export certificate and private key
In the Console window, in the Console Root section, expand Certificates (Local Computer). Expand the folder that contains the certificate that you want to export/back up, and then, click the associated Certificates folder. Be sure to check both the Personal and Web Hosting folders. In the center section of the window, right-click on the certificate that you want to export/backup and then click All Tasks > Export to open the Certificate Export Wizard.
Click the Next button on the Welcome to the Certificate Export Wizard window.
On the Export Private Key page, select Yes, export the private key option and then click the Next button.
On the Export File Format page, select Personal Information Exchange. Check the Include all certificates in the certification path if possible checkbox. This will ensure that all intermediate certificates will be included as part of the export. Click the Next button to continue.
On the Security page, check the Password checkbox. Enter and confirm your password and then click the Next button.
On the File to Export page, browse and select the location where you would like to export/backup the file.
On the Completing the Certificate Export Wizard page, verify the settings and then click the Finish button. You should receive The export was successful. message.
The exported .pfx file contains your certificate, intermediate certificates as well as the private key. You can import the certificate, intermediates as well as private key to another Windows server using the .pfx file. You can also use the SSL Converter online tool to convert the .pfx (PKCS#12) file to any other format you may need in the future.