It seems is no longer possible (it was in ArcMap) to Add field to Raster Attribute tables, except through the Add Field geoprocessing tool.
The Add field button in the table window is inactive and it shows the message "This command is currently unavailable. The project has unsaved edits or the table or its schema is read only".
My opinion is that in ArcGIS Pro ArcGIS raster table schema is inactive by default.
Can anyone confirm (or deny) this?
I'm using ArcGIS Pro 2.8 and it's the same in 2.9
I checked this, in Pro 2.8. It looks like you have an Esri Grid (the OID tipped me off); the raster table is an INFO table. It appears the Add Field button does not work with Esri Grid tables. Funny, because you can edit the INFO table contents!
If you convert the raster to .tif (I recommend this) or FGDBR you can add a field from the attribute view. However (interestingly) the Add Field tool works fine to add fields to an Esri Grid INFO table.
Yes, Add Field button worked fine for me with a raster .tif table. I would make sure you don't have an edit session open. It's possible file naming is an issue, and there are so many things that can make a layer non editable and it is sometimes not easy to diagnose! Try the Add Field tool maybe you'll get a useful error message.
Thanks curtvprice, no edit session open, no messages when I use the Add Field Tool.
Do you think the problem (for the Add field command unavailable in the table view) could be the file naming?
integer raster, it works from the toolbox, not the table. Pro 2.9
Path and filename are short and checked.
Build raster attribute table
Go to Fields View