Can you upoad the FME-log file?

I'm having the same issue. The writer and reader are both SDE and the writer "Preserve GlobalID" parameter is set to Yes. But the output GlobalID all have "{00000000-0000-0000-0000-000000000000}".

According to this document, the GlobalID should be preserved in the output.

http://docs.safe.com/fme/html/FME_Desktop_Documentation/FME_ReadersWriters/geodatabase/GEODATABASE_SDE_writer.htm?Highlight=globalid

The reason I want to preserve GlobalIDs is because I have a polygon with a related table that I want to use for updating another polygon layer with a related table with the same relationship class (GlobalID -> GUID). Maybe there's a better way to do this in FME, but it seemed like preserving GlobalIDs was my answer.

I'm using  FME 2020.2.1.0 (20201130 - Build 20806 - WIN64)

If it helps anyone, here is the error I get in FME.

Could not register GlobalID column 'GlobalID' in table 'DBO.sourcetable'. The error number from ArcObjects is: '-2147155969'. The error message from ArcObjects is: { s:Microsoft]sODBC Driver 17 for SQL Server]rSQL Server]The CREATE UNIQUE INDEX statement terminated because a duplicate key was found for the object name 'dbo.sourcetable' and the index name 'UUID_271'. The duplicate key value is (00000000-0000-0000-0000-000000000000).] 0development.DBO.sourcetable]}

@danielwebb​ Preserve GlobalID : Yes should be working for you. On your writer feature type, make sure the GlobalID field is of type GlobalID. Does this feature class participate in a relationship or attachment or something?

I've attached a small example (FME 2021.2).

If the problem persists then please attached a small example, and also export the target geodb data model using the ArcCatalog to Export XML workspace Document (Schema only). If the data is confidential then perhaps contact you FME provider and open a support case.

Yes, the feature class has a relationship class. Does that make a difference on whether the "Preserve GlobalID" parameter works?

@danielwebb​ I think a relationship class might complicate things. Do you have a small example that you can attach?

I can try putting together a testing example to share, but not sure when I'll have the time at the moment.

But I think I solved the issue at least for now.

Since a GUID can be copied and not unique, in ArcGIS Pro I set up an attribute rule on the source feature class to copy the GlobalID into a GUID field type called GlobalID_Origin. On the related layer and table being updated (the destination), I set up the relationship to be based on GlobalID_Origin --> GUID. In FME, the GlobalID_Origin from the source feature class passes the GlobalID_Origin to the destination feature class. And the source related table passes the GUID values to the source relationship table. This keeps the "original" GlobalID values, and the relationships of the source and destination are the same.