Error: Unable to create or open the default database

Error Message

When opening ArcMap, the following error message is received on start-up:

"Unable to create or open the default database."

This error is due to one of the following conditions:

  • Insufficient disk space or incorrect access to: <pathname>
  • Invalid or corrupt installation of MSXML.


In ArcGIS 10, one of the start-up processes is the creation and/or validation of a default file geodatabase in the <User Profile>\MyDocuments\ArcGIS folder for the user executing the software. The default geodatabase is used in many tasks throughout the application and is required to effectively run the software.

As a result of one of the conditions described in the error message, the default geodatabase cannot be successfully created and/or validated and the start-up of the application fails.

Solution or Workaround

To circumvent this issue, follow the steps below:

  1. In Windows Explorer, right-click and open the properties of the drive described in the error message, such as the C:/ drive.
  2. Under General, ensure adequate free space is available on the drive. The default file geodatabase requires no more than .5 MB.
  3. In Windows Explorer, browse to the path described in the error message.
If the folder contains multiple versions of the Default.gdb, skip ahead to Step 6. Multiple default geodatabases have unique names and they follow this naming convention: Default.gdb, Default1.gdb, Default2.gdb, etc. In Windows Explorer, file geodatabases appear as folders with the name of the geodatabase followed by a .gdb extension.
  1. Right-click the folder and open its properties.
  2. Under Security, ensure the user attempting to execute the software has Read and Write permissions.
  3. If one or more Default.gdb folders exist in the workspace described in Step 3, delete it.
  4. Rename the Default.gdb file. For example: 'Default_old.gdb'. A new Default.gdb file is created when ArcMap loads.
  5. Install MSXML 4.0 Service Pack 3 (Microsoft XML Core Services).
  6. Restart the machine and launch ArcMap. It now starts successfully.

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