It sounds like your permissions may be messed up or restricted. I do not know if you are trying to access D: by the D$ share, through some share you have established, or if using a share, if that share is persistent. If you are having issues with your domain admin account accessing your D$ share, try changing your GPO settings in Computer Settings\Windows settings\Security settings\Local policies\Security options. Look for User Account Control: Run all administrators in Admin Approval Mode and set it to disabled.
For Microsoft SQL you may be missing file system permissions for SQL or using the wrong account. if you need to add back permissions to a particular section of your file system you need to add the full service name similar to an account, it cannot be browsed (NT Service\MSSQL$SQL2016).
You can also look at the following: Using Service SIDs to grant permissions to services in SQL Server