Error: Unable to start iomgr. The ArcSDE service (esri_sde) service could not be started

Error Message

This is a Microsoft SQL Server specific problem for Windows only authenticated users.

Starting the ArcSDE service during post install returns the following error message:

“unable to start iomgr”.

Starting the ArcSDE service, by way of the command prompt, by typing 'net start <service_name>' returns the following error message:

"The ArcSDE service (esri_sde) service could not be started."

The ArcSDE service does not report an error; however, the esri_sde.log reports the following:

ArcSDE 9.0 SQL Server Build 1970 Mon Jan 31 18:13:12 PST 2005
IDBInitialize::Initialize Failed
DB_open_instance() PCC_connect error: 18452
init_DB DB_instance_open_as_dba: -51
DBMS error code: 18452
Microsoft OLE DB Provider for SQL Server: Login failed for user 'sde'. Reason: Not associated with a trusted SQL Server connection.


Microsoft SQL Server is set to Windows-only authentication in the security settings.

Solution or Workaround

This can be resolved by setting the security settings to 'mixed mode'.

  1. Start Microsoft SQL Server's Enterprise Manager console for SQL Server 2000 (Management Studio for SQL Server 2005).
  2. Right-click on the SQL Server instance and select Properties to open the Instance Properties.
  3. SQL Server 2000
    Navigate to the security tab and change 'Authentication' to 'SQL Server and Windows'.
    [O-Image] Security settings for SQL server instance
  4. SQL Server 2005
    Navigate to the security page and select the radio button under Server authentication for 'SQL Server and Windows Authentication Mode'.