If you have hard deleted (Shift-delete) a message or mail-item from a shared mailbox you may notice that the option to recover deleted items is greyed out and you cannot select it.
Hard deleted items can be restored from your deleted items folder quite easily but this option is not available in certain circumstances or for certain folders, including folders in shared mailboxes. The default deleted item retention in Office 365 is 30 days.
Recover deleted items greyed out
You can use the DumpsterAlwaysOn registry in order to be able recover deleted items
Setting the DumpsterAlwaysOn registry value
As stated above, if you find that the “Recover Deleted Items” option is grayed out then you need to set the DumpsterAlwaysOn Registry value.
- Key for 32-bit Outlook on a 32-bit version of Windows
- Key for 32-bit Outlook on a 64-bit version of Windows
- Key for 64-bit Outlook on a 64-bit version of Windows
Create a new DWORD value with the name of DumpsterAlwaysOn and set the value to 1.
On my own system (Windows 7 64-bit with Outlook 2013) the “Options” key was not present and I had to create it first before adding the DumpsterAlwaysOn DWORD.
After you have made this change you need to restart Outlook for the changes to take effect and then you should see the option become available:
Recover Deleted Items for non-mail folders in Outlook 2010
Even though the Recover Deleted Items feature works for all non-mail folders in Outlook 2010, the feature is not available by default on the Folder tab for these type of folders. So if you have deleted a task or a calendar appointment and need to recover it, here is how to do it.
- Go to File, then Options
- Choose “Quick Access Toolbar”
- Change the “Choose commands from” list to “All Commands”
- Select “Recover Deleted Items…” from the list
- Click on the “Add > >” button.
- Click OK.
You should then have a new option on your quick access ribbon that will enable you to recover deleted items from any folder that contains items that can be recovered.
Microsoft have some more information and a “Fix it for me” procedure on their website: