Directory and Resource Administrator 6.60
Error performing task: The security ID structure is invalid ' when granting a user permissions to another user's mailbox.
When attempting to grant an account permissions to a mailbox using the Directory and Resource Administrator MMC interface, the following error may occur:
Error performing task: The security ID structure is invalid.
ID no: 80070539
Microsoft CDO for Exchange Management
This issue occurs when one of the security trustees on a mailbox cannot be resolved. This can occur if the account was previously deleted but is still listed in the ACL or if the SID is corrupt.
The above described problem has been corrected in Directory and Resource Administrator (DRA) version 7.0 and later. To resolve this problem, please upgrade to the latest version of DRA.
Download: Directory and Resource Administrator (requires username and password)
The following workaround is available if you are running DRA version 6.60 and earlier:
Look for and delete any ACE for which the validity of the SID cannot be verified. The ACE in question may be inherited so deleting it from the administrative group could also remove it's permissions throughout the environment.