Outlook has always been slow when using mapped drives, even when you aren't going to use the mapped drive in Outlook. Outlook will to try to connect to every drive before it will let you insert attachments. It was so bad that I stopped using mapped drives.
I can't attach a file to an email in Outlook 2010 unless I delete all network places and mapped drives. All I get is the frozen "initializing places" dialog. Is there a less drastic workaround?
For Outlook 2010, you first need to install this hotfix Description of the Office 2010 hotfix package (Mso-x-none.msp): June 26, 2012.
After installing the hotfix, set the DisableLoadLookIn registry key.
HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Common\ DWORD: DisableLoadLookIn Value: 1
If you don't want to edit the registry, you can use the ready-to-use reg file below.
Download the registry file then double click to run it. Ok the dialogs to add it to your registry.