unable to disable archiving

Team,

Can someone please help me to solve this issue:

We have around 1,200 disabled user accounts, as part of archival project , we have performed below tasks.

1. Moved all disabled users to dedicated exchange server
2. All mailbox content has been exported as PST
3. Disabled user Account and mailbox hidden from GAL
4. User has been added to EV Provisioning group

Archive is available for all disabled users on EV.

While running archiving task for dedicated exchange server and based on the report  , most of the mailboxes not archived because mailbox is hidden or AD Account is disabled.

Now we are in the process of performing below tasks.

1. Disable Archiving for all Mailboxes those who are on dedicated exchange server ( While trying to disable Mailbox for archiving it is showing only 3-4 mailboxes out of 1200 , even existing mailboxes are not listed to enable /disable mailbox for archiving) , do I need to enable both registry key ? so that the mailboxes are listed to disable ? .my issue is in case if I enable registry key all 1200+ mailboxes will start archive and it may create load on dedicated exchange server for disabled users and on EV ?

1. To Archive mailboxes which are hidden

http://www.symantec.com/connect/blogs/processing-hidden-mailboxes-enterprise-vault

1. Archive Mailboxes whose AD accounts  are disabled

https://www.veritas.com/support/en_US/article.TECH76587

1. Enable few mailboxes on EV and check

EV version is 11 and OS version Win2012

Regards

Srinivasa K