RE: Hierarchy button on Accounts Menu
Microsoft have provided this work around as per notes below.
Reason!
Reason for having to create this new security role for all users.
The system is not able to read the permission on any of the existing security roles, and therefore a new security role needs to be created, and given this permission, including the admins.
Imagine the box on the security role is checked, but nothing is happening in the background, it is as if it is not selected at all, but the system does not see that and shows it as existing.
But then when the system checks if the user, any user, has that permission, it does not find it, so it does not show the hierarchy.
The role needs to be given to ALL the users including admins because if just one user without the role logs onto the system, all the next users logging in, even if they have it, will not see the hierarchy again.
This is why it is difficult to reproduce, it happens only after an iis reset, which is not something one would relate to in CRM.
Microsoft have mentioned it is a known issue and the teams are working on having a fix so that this workaround will not be needed in the future.
Answer! Workaround
You need to create a new security role, give the PrivReadHierarchyRule role and assign the role to ALL the users in the system.
Client!
Has confirmed that the Heirarchy functionality is now working again as expected.