Name of the deployment preview error
Modifying an element from a managed package may not be allowed
Sample error message
Modification of element salesforce.SBQQ__SearchFilter__c.field.SBQQ__FilterSourceField__c from managed package with namespace SBQQ may not be allowed.
When will I see this deployment preview error?
This error occurs when you select an element that comes from a managed package, for example, a picklist from the CPQ managed package.
Not all metadata from a managed package can be modified. What metadata can be modified depends on the author of the package, and Salto has no way of knowing beforehand if the element that you selected has been configured to allow modifications.
So, for example, if you make add a new picklist value to a picklist field from CPQ, you will get this warning
In this particular scenario, you will be able to modify the picklist, as it is a modifiable metadata type. The warning is just there to remind you that not all elements from this managed package can be modified.
How does this affect my deployment?
This is just a warning. Salto will attempt to deploy the element.
How can I fix this error?
There's nothing to fix. If the managed package is configured to allow modifications to the selected metadata type, the deployment will succeed.
You can learn more about deployment preview errors here.