User is not allowed to perform update operation [CMM000126] error occurs while trying to update user data fields under the 'User Defined' tab in the Computer Properties windows.
The user account has been given Manage (VRX) permissions for Asset Group and Change (VRXWD) permissions for Computers.
CA Client Automation - All versions
For the user account to be able to update the user data fields, the user account needs to have 'Write' permissions on Asset Groups.
'Write' permissions can be assigned in two ways:
1. Assign 'VRWX' permissions to 'Asset Groups' under Security Profiles for the user account.
2. Right-click the computer group (in this example - All Computers) and select 'Permissions. Select the 'user account' and give 'VRWX' permission under object access.