Here's the situation:
- Single Sharepoint web front end server in domain A.
- Site is also used by members of domain M.
- There is a one-way trust from domain A to M.
- The people picker has been set up to search in both domains using the peoplepicker-searchadforests property and works fine.
Here's the problem:
- When trying to assign a task in a sharepoint task list, the people picker can be successfully used to pick a user that is in domain M and populates the field with their username. However, when saving the task, the error "The user does not exist or is not unique." is thrown, and the tasks assignment doesn't change.
- This only happens with users that are in domain M AND do not already have a corresponding sharepoint user account. They only have permission to access the site by virtue of being a member of a domain security group that is in a sharepoint group.
- If I explicitly add the users domain account to a sharepoint group, the task assignment works fine.
What might the problem be?