The exclamation marks in the SOLIDWORKS Feature Manager Design tree are the result of unresolved sketch profiles; planes etc. that might have been created during the design process and need to be edited.
To find out what these errors are:
Make sure “Show errors every rebuild” is checked under the Tools > Options > System options.
Every time the rebuild option in SOLIDWORKS is used, a window describing the errors will open up.
To fix the errors shown in the above window:
Go to Tools > Feature Statistics.
The “Feature Statistics” window shows all the features within the part.
Select a feature and right click to Delete or Edit.