Symptoms:
At times on launching Common Asset Viewer in CA Service Desk Manager, this error message appears:
"Error: An invalid URL was specified; The SELECT permission was denied on the object 'tng_managedobject', database 'mdb', schema 'dbo' "
Resolution:
The error occurs because of incorrect permissions on the MDB database.
- Login to SQL Server Management Studio as ServiceDesk or SA
- In the Object Explorer, expand Databases
- Right click MDB->Properties.
- Click on Permissions.
- By default only the ServiceDesk user is listed.

- Expand MDB database, click on Security->Roles->Database Roles
- Double click on amsgroup and verify if ServiceDesk is listed as a Role Member. If not, click on Add to find ServiceDesk user and add it to the role members.

Note: Either the ServiceDesk user can be a Role Member to the amsgroup or amsgroup can be granted permissions on MDB directly.
Additional Information:
tng_managedobject - Details on the main table to store all the managed objects. e.g. device, agent, unispace etc.