When you try to download an Offline Address Book (OAB) for a profile in Outlook 2013 or Outlook 2010, you receive the following error message:
Task '<profile name>' reported error (0x8007007A): 'Unknown Error 0x8007007A'.
Value data for the 001e660e registry entry is used to control where the OAB files are stored by Outlook. If the value data for the 001e660e registry entry is missing, Outlook cannot store the OAB files successfully. The registry entry is located in the following registry subkey.
- Outlook 2013HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Outlook\Profiles\<profile name>\<subkey varies for each Outlook profile>\
- Outlook 2010HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows Messaging Subsystem\Profiles\<profile name>\<subkey varies for each Outlook profile>\
- To determine the subkey that varies for each Outlook profile, search the <profile name> subkey for the 001e660e registry entry. To do this, see method two in the resolution section.
- The registry value does not exist by default in most Outlook profiles. It typically exists only if you have configured an Outlook profile by using a .prf file that has the setting that specifies the path for the OAB files.
- If you configure an incomplete .prf or .msp file in Outlook 2010 or Outlook 2013, this may cause a blank value for the registry key. For more information, see (KB2923056) 0x8007007A error when you try to download an Offline Address Book because of an incomplete .prf or .msp file .