Can't configure an Outlook profile when the email address starts with "aux" or "con" prefix

Vzťahuje sa na: Microsoft CRM client for Microsoft Office OutlookOutlook 2013Microsoft Outlook 2010


A user configures a new Microsoft Outlook profile by using an email address that resembles the following:

In this situation, the following error message is returned:

Cannot start Microsoft Outlook. Cannot open the outlook window. The set of folders cannot be opened. Unknown error.

The screenshot for the error message


Outlook uses the email address as the name for the data file, as in However "con" is one of the MS-DOS device driver names. Windows doesn’t let you use an MS-DOS device driver name when you create a file. The following is a list of the MS-DOS device driver names:
CON Keyboard and display
PRN System list device, usually a parallel port
AUX Auxiliary device, usually a serial port
CLOCK$System real-time clock
NUL Bit-bucket device
A:-Z:Drive letters
COM1 First serial communications port
LPT1 First parallel printer port
LPT2 Second parallel printer port
LPT3 Third parallel printer port
COM2 Second serial communications port
COM3 Third serial communications port
COM4 Fourth serial communications port


To resolve this issue, use one of the following methods.

Method 1: Change the email address of the affected mailbox on the server side 
Method 2: Change the name of the data file in the Outlook profile
To do this, follow these steps:
  1. Exit Outlook.
  2. In Control Panel, open the Mail item, and then click E-mail Accounts.
  3. Click Change, and then click More Settings.
  4. On the Advanced tab, click Outlook Data File Settings.
  5. Select the File name, and then delete the period (.) after the aux or con prefix. For example, if the file name is - aux.user.ost, change it to – aux.user.ost.

  6. Click OK.
  7. When you're prompted for confirmation, click Yes.

  8. Click OK.
  9. In the Change Account window, click Next, and then click Finish.
Outlook will now start correctly.