I have a customer that had their 2008 DC crash with no backup.  They created a new AD domain with a new name with all the same users.  Then they exported all mailboxes as PST files and imported them into the recreated mailboxes.  Now, when trying to modify a calendar entry, they get a "Don't have permission" error.

My research says this is a known problem that has to do with an incorrect LegacyExchangeDNS attribute.  It can be fixed by using the old AD's attribute and adding it as an X500 address on the new Domain.  Unfortunately, the old DC is toast.

Any thoughts on how to fix this?

Thanks!

That would be the LegacyExchangeDN attribute.  If you can find the old values for that attribute, you can indeed add them as a proxy address of type X500.  Maybe if you use a tool like MFCMAPI (which you can download from Codeplex, I believe) you can look at the MAPI properties of the calendar items and find out that attribute and add it to AD.

Maybe it's just easier for users to recreate those appointments.  That would probably work a lot better in the long run.

Hi,

According to your description, I understand that all mailboxes are exported as PST files and imported to the new created mailboxes.

The PST exporting and importing may lost some permission during New-MailboxImportRequest importing. Please use Microsoft Exchange Server MAPI Editor (MFCMAPI) tool to export calendar data and import it to new mailbox to have a try. Also check the Calendar permission for the Calendar folder:

http://blogs.technet.com/b/outlooking/archive/2010/05/14/useful-tools-while-troubleshooting-outlook-issues-3-mfcmapi.aspx

Additionally, here is a helpful KB:

https://support.microsoft.com/en-us/kb/2783959

Regards,