Tuesday, November 29, 2011

Error: Cannot create another system semaphore

When trying to start the Dynamics Ax AOS service, the attempt fails.
You may receive following error message:

Error: Cannot create another system semaphore

When you check the Windows event log, you may come across following error:

Fatal SQL condition during login.

Probable causes:

  1. The SQL Server service is down, verify this first.
  2. The account that has been setup to start the AOS service, does not have the proper security rights for the Ax SQL database.
Regarding number 2:
If you copy your database from one environment to another (from Production to Test for example), make sure you have the right security setup in place.  Does the startup account used for the AOS service have access to the SQL database?

Once the account has access, make sure it has proper access.
If you don't want to give it the db_owner role, make sure at least following roles are assigned to the service account

• db_ddladmin
• db_datareader
• db_datawriter

Also make sure permission to execute both stored procedures is in place.

After you verified the above, you should be able to start the AOS service.


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  2. SQL database was down, had to recover and then restart SQL services.

  3. Your blog is very useful for me,Thanks for your sharing.