If you copy a specific unit(ex: lurker), all your base actor data will be messed up.
It doesn't messes up your custom data, but the default data will be all corrupted.
For instance, if you have a custom actor data named "ABCD" then copy and paste lurker in unit section.
Save and reopen your map.
And check the actor section and you'll see that almost all default actor's parent IDs changed into ABCD.
I found this bug last summer and I wonder why it is still bothering me.
Now I have to start all over again, thanks to blizz.
When you get the same problem as above, save the map to .SC2Components, NOT SC2Map.
Open you map and you should click "Save as..." to do this.
Then you'll see a folder created instead of the Galaxy Editor file.
Inside of that folder, look for EnUS.SC2Data>LocalizedData and there would be 4 .txt files - GameHotKeys, GameStrings, ObjectStrings, TriggerStrings.
These are not xml files so all you have to do is just correct the data and save it.
In my case, the actor's default name was the problem so I modified ObjectStrings.txt.
All the default & custom actor names should be in there.
If you copy a specific unit(ex: lurker), all your base actor data will be messed up. It doesn't messes up your custom data, but the default data will be all corrupted. For instance, if you have a custom actor data named "ABCD" then copy and paste lurker in unit section. Save and reopen your map. And check the actor section and you'll see that almost all default actor's parent IDs changed into ABCD. I found this bug last summer and I wonder why it is still bothering me. Now I have to start all over again, thanks to blizz.
@rosyjay: Go You could try to repair it in the map's xml files. I'm a victim of that, too. But it didn't harm me, yet.
@Ahli634: Go
Solved it! thx!
It might be interesting for everyone how you solved it? Somehow within the editor or deleting the unit in the xml file?
He replied to you , saying he solved it and thanks. Which means your suggestion fixed it.
@ibebusiness: Go
Still doesn't answer the question from a third party such as me though.. How exactly are xml files repaired?
@FuzzYD: Go
When you get the same problem as above, save the map to .SC2Components, NOT SC2Map. Open you map and you should click "Save as..." to do this. Then you'll see a folder created instead of the Galaxy Editor file. Inside of that folder, look for EnUS.SC2Data>LocalizedData and there would be 4 .txt files - GameHotKeys, GameStrings, ObjectStrings, TriggerStrings. These are not xml files so all you have to do is just correct the data and save it. In my case, the actor's default name was the problem so I modified ObjectStrings.txt. All the default & custom actor names should be in there.