Ok. Solved it.
Not by dropping CUS and USR layers, but it appears that there where orphaned records in the dbo.modelelement database.
Maybe it helps someone:
1. Open SQL Management studio
2. Go to AX database and to dbo.modelelement table
3. Right click, select "Edit top 200 rows"
4. Click on SQL button in button bar
5. delete query that is pre-defined, and enter:
[quote]
SELECT ElementType, RootHandle, ParentHandle, ElementHandle, Name, AxId, ParentId, Origin, PartOfInheritance
FROM ModelElement AS Element
WHERE NOT (EXISTS (
SELECT 'x' FROM [dbo].[ModelElementData] AS Data
WHERE Element.ElementHandle = Data.ElementHandle
))
ORDER BY Element.Name ASC
[/quote]
Gave no results in my case. So second SQL query:
[quote]
SELECT ElementType, RootHandle, ParentHandle, ElementHandle, Name, AxId, ParentId, Origin, PartOfInheritance
FROM ModelElement AS Element
WHERE (ParentHandle <> 0) AND (NOT EXISTS
(SELECT 'x' AS Expr1
FROM ModelElement AS Parent
WHERE (ElementHandle = Element.ParentHandle))) OR
(RootHandle <> 0) AND (NOT EXISTS
(SELECT 'x' AS Expr1
FROM ModelElement AS Parent2
WHERE (ElementHandle = Element.RootHandle)))
ORDER BY Name
[/quote]
Gave 81 records in my case.
6. Then all orphaned elements are shown.
7. delete them (select all, right click delete)
8. Continue installation
