IBM Support

Error occurs when numerous users log in to the ClearQuest server at the same time



Users receive errors when logging in to the IBM Rational ClearQuest server at the same time.


The users might receive one of the following errors:

  • Throw: Attempt to call function "RegOpenKeyEx" on registry key "HKEY_LOCAL_MACHINE\Software\Rational Software\ClearQuest\7.0.0\Core\Databases\<dbset>\<dbname>" failed. System error: The system cannot find the file specified.
  • Throw: The database "<dbname>" belonging to the dbset "<dbset>" is not properly registered as a user database. There may be a problem with the dbset or its registration on the current machine. Check the registration or recreate the database connection and try again.
  • Throw: The database "<dbname>" belonging to the dbset "<dbset>" is not registered.
    Please first make sure you entered the correct database name and the correct dbset name, and then make sure the database and the dbset are registered.


The Rational ClearQuest login process for Microsoft Windows accesses the Windows registry to obtain database connection information. The login errors are caused by a known bug in Microsoft Windows API RegOpenKeyEx and RegQueryValueEx, "BUG: Registry access from multiple threads might fail". For more information, see

Resolving The Problem

To work around this issue, decrease the workload of the Rational ClearQuest Server to reduce the occurrence of these errors. If users receive one of these errors, have the users try logging again.

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Document Information

Modified date:
15 November 2018