Hi Liam Wilson,
you must first ensure that your CA's computer account has NTFS Write permissions to the newly created folder on that dedicated volume. Then open the Certification Authority console, right-click your issuing CA, and select Properties. Navigate to the Extensions tab and choose CRL Distribution Point from the drop-down list. Click Add to define your new local path on the dedicated volume, being sure to insert the required CA name, CRL name suffix, and Delta CRL variables ending in .crl so the files are named correctly. After adding the path, highlight it in the list and check the boxes at the bottom of the window to publish CRLs and Delta CRLs to this location.
Next, highlight the original path pointing to your C: drive and remove it so the system stops attempting to write to the full disk. Click OK to apply these changes, which will automatically prompt you to restart the Active Directory Certificate Services service. When the service restarts, open an elevated Command Prompt and execute the certutil -crl command.
Hope this answer has brought you some useful information. If it did, please hit “accept answer”. Should you have any questions, feel free to leave a comment.
VPHAN