Intermediate certificates help complete the "Chain of Trust" from an end-entity certificate back to a root certificate. Intermediate certificates must be present ahead of time prior to setting bindings in IIS or applying services in Exchange.
1. Go to Start > Run > mmc. Press Enter:
2. In the MMC, go to File > Add / Remove Snap-In...
3. Choose the Certificates snap-in. Click Add.
4. Choose Computer Account. Click Next >
5. Choose Local Computer. Click Finish.
6. Click OK to exit the snap-in window.
7. In the MMC window, expand the following sections: Certificates (Local Computer) > Intermediate Certification Authorities > Certificates
8. Right-click the Certificates folder and go to All Tasks > Import
9. Choose Local Machine. Click Next
10. Click Browse on the next window:
11. Choose the intermediate that you wish to import and click Open
12. Click Next on the Certificate Import Wizard:
13. Make sure the Certificate Store is specified as Intermediate Certification Authorities. Click Next.
14. Click Finish
15. Click OK when the certificate imports successfully.