"Hard deleting" an item in Exchange 5.5 parlance means to delete something before moving it to the Deleted Items folder. When an item is moved to the Deleted Items folder, it can be easily recovered from there before the folder is emptied, but once the folder is emptied, those messages are generally gone for good.
However, if you are using a mail client on an Exchange 5.5 mailbox, items that have been removed from the Deleted Items folder can still be recovered, provided the Exchange Server has been configured to retain deleted items. Modifying the retention time for Exchange Server -- the time between when a message is marked as deleted and when it is actually erased from the message store -- accomplishes this.
To determine what the deleted mail retention time is for your server, start up the Exchange Server Administration program and open the mailbox or public folder you are dealing with. Click the Limits tab for that folder or mailbox, and look at the Use This Value (Days) box. This is the time limit that messages marked as deleted are retained in the Exchange message store in days. Setting this to 7, for instance, will retain all deleted messages for a period of one week.
If you want to set this value for a whole store rather than just a single mail store, open the Server container and select the information store you want to edit. Select the General tab for that store, and then enter the appropriate value in the Deleted Item Retention Time (Days) box.
Clients can also hard-delete mail in folders other than the Deleted Items folder. If you open the Inbox in Outlook, select a message and hit Shift+Delete, the item is hard deleted. To provide a buffer of safety for messages deleted in this fashion, you'll need to edit the Registry of the client machine. Under the key HKEY_LOCAL_MACHINESOFTWAREMicrosoftExchangeClientOptions, add a DWORD value named DumpsterAlwaysOn and set it to 1. Be sure to restart Outlook after doing this. If you then open the Tools menu in Outlook and look in the Deleted Item Recovery section, you'll see a list of items hard-deleted during the retention time set for the server you're connected to.
Note that items deleted from non-mail folders, such as Contacts and Notes, cannot be recovered in Outlook 98. In Outlook 2000, 2002 and above, however, Deleted Items functionality works on everything.
Serdar Yegulalp is the editor of the Windows 2000 Power Users Newsletter.