SYMPTOM:
The user notices that when running the Project Merge Wizard in Strategy Object Manager 9.x and 10.x, the following error is given and the merge ultimately fails:

'The following error has occurred and is not recoverable. Once this message box is closed, Project Merge wizard will close. Method '~' of object '~' failed'
CAUSE:
One of the causes for this issue is an attribute or set of attributes that have an inconsistent object definition in the metadata.
This can be confirmed by running the Strategy Scan MD tool in 'check' mode and the following entry can be found in the Problems.log log file:
Error : <Attribute_Name>'s attribute forms collection is empty.
Recommended action to fix the problem: Remove <Attribute_Name> from metadata or add an attribute form.
ACTION:
The user needs to run the Strategy Scan MD tool in 'fix' mode against the metadata to correct the inconsistent attribute object definition.
Once this action has been taken, no error will be thrown and the Strategy Project Merge Wizard will finalize and take place successfully in Strategy Object Manager 9.x and 10.x.