An Unknown Error Occurred Adding Data File In Outlook 2016 Error: 0x80004001 Posted on by Webmaster IT Support Forum › Forums › Windows › Windows 10 › Applications › An Unknown Error Occurred Adding Data File In Outlook 2016 Error: 0x80004001 Tagged: 0x80004001, Outlook, Outlook 2016, PST This topic has 0 replies, 1 voice, and was last updated 6 years, 4 months ago by Webmaster. Viewing 0 reply threads Author Posts July 24, 2017 at 11:03 am #2158 WebmasterKeymaster When trying to add a new Data File in Microsoft Outlook (Control Panel -> Mail), I get this error: Microsoft Outlook An unknown error occurred, error code: 0x80004001 To fix this, I went to the Control Panel -> Mail and set up a new Profile abandoning my old one. Author Posts Viewing 0 reply threads You must be logged in to reply to this topic. Log In Username: Password: Keep me signed in Log In