Why am I seeing different designators in my schematic?

Solution Details

In a schematic document, when the Board Level Annotation Command is invoked, a special file is created in the project directory that has the project name and an *.ANNOTATION extension. Once this file is created, this file can affect the way your designators are displayed and handled. There is no automated way to remove this file. This article will show you how to remove this file from your project.

When a project is compiled (or dynamically compiled with Altium Designer 20 and above), for each schematic page, there will be at least two tabs at the bottom of the page.  

The first tab is the Editor tab. This has the physical designators of the components.
The second tab is the Compiled tab and contains the logical designators of the components.

Normally, the designator values in each of these tabs is the same unless multichannel annotation is used.
However, if an Annotation file has been added to the project, the only way to update the "Compiled" tab designators is through the Board Level Annotation dialog. The values assigned here will override the designator values in the Editor tab. The Compiled tab designators are those which will transfer to your PCB document.

If you had not intended to use Board Level Annotation, the .Annotation file will need to be manually deleted. An .Annotation file is created just by merely invoking the command. These steps will remove the Annotation file from your project:

1. First, right-click on the top level file in your project, the PrjPcb file, and choose Explore. This will open the project directory in Windows Explorer.
2. In Altium Designer (or Nexus), close the project (or close Altium Designer). 
2.1. This can be done by right-clicking on the project and selecting Close Project.
3. Once the project is closed, switch back to Windows Explorer.
4. Delete the .Annotation file. This file will have the same name as your project with an .Annotation extension.
5. Once the file has been deleted, return to Altium Designer and reopen the project.
6. You will receive a message that the Annotation file is being removed from the project. You can now save the project.

At this point, your Editor tab and Compiled tabs should now have the same annotation values and the Annotation file will no longer be referenced.

NOTE: If you only delete the .Annotation file from your project and not following the steps above, the next time you open your project you may see a warning message that the .Annotation file was found and is being added to the project.

For more information on Board Level Annotation, please refer to our online documentation: 
https://www.altium.com/documentation/altium-designer/workspacemanager-dlg-annotationform-2board-level-annotate-ad