This morning we had an incident with a customer who during the night had failed over their SQL cluster during the night and then failed it back again and now AX had stopped working. The error was this:

The problem is that when SQL is restarted the permission on tempdb is reset. AX solves this is a “special” way. When AX is installed the install created a stored procedure in master on the SQL server which it calls to set the permissions in case they get lost.

These was unfortunately missing on one of the nodes so I used Management Studio to script them out and the create them on the node where they were missing

/Johan