Without knowing what 'exclude' utility you are using, here are a few things to check that are common to all. (these refer to those that create a '.bgl' exclude file, like SBuilder or ExcBuilderV2)

Do you have 'bglcomp.exe' and 'bglcomp.xsd' properly installed (Bglcomp SDK) and MSXML4 installed? Does the utility know where 'bglcomp.exe' is?

Coordinates: Must define the NW corner and SE corner of the rectangle. Must be accurate (if manually entered)as an error of only a few of minutes can place the exclude out of your 'view'.

Are you selecting the proper objects to exclude? To get rid of 'autogen' objects select 'all objects'.

Is the utility creating the '*.bgl' file? Depending on the utility you may or may not get an error message when compiling so look for the file.

Are you, or the utility, placing the '*.bgl' in an active FS scenery sub folder, example; ..\Addon Scenery\scenery\..or the same active ..\scenery\..sub folder as your project's scenery '.bgl's' ?

Dave