Hello everyone
I am getting this error message when I try to version a feature dataset in ArcSDE 10.4.1, with Ms SQL Server 2014.
The only key I see in the feature class is the one related to the OBJECTID column in the feature class that shows the error message.
It looks like this error is related to duplicated key values when the key is unique.
Error: Failed to register as versioned. Unique indexes can't be specified for multiversioned tables
Was this table created using SQL?
In ArcCatalog, right click the feature class you are trying to register as versioned-> copy-> paste it back into the same geodatabase keeping the _1 naming convention.
Register the new feature as versioned. Does this work?