diff --git a/framework/src/Volo.Abp.Cli.Core/Volo/Abp/Cli/ProjectModification/DerivedClassFinder.cs b/framework/src/Volo.Abp.Cli.Core/Volo/Abp/Cli/ProjectModification/DerivedClassFinder.cs
index db39a660ce..4cf3209955 100644
--- a/framework/src/Volo.Abp.Cli.Core/Volo/Abp/Cli/ProjectModification/DerivedClassFinder.cs
+++ b/framework/src/Volo.Abp.Cli.Core/Volo/Abp/Cli/ProjectModification/DerivedClassFinder.cs
@@ -29,8 +29,7 @@ namespace Volo.Abp.Cli.ProjectModification
 
             var csFiles = new DirectoryInfo(csprojFileDirectory)
                 .GetFiles("*.cs", SearchOption.AllDirectories)
-                .Where(f => !f.DirectoryName.StartsWith(binFile))
-                .Where(f => !f.DirectoryName.StartsWith(objFile))
+                .Where(f => f.DirectoryName != null && (!f.DirectoryName.StartsWith(binFile) || !f.DirectoryName.StartsWith(objFile)))
                 .Select(f => f.FullName)
                 .ToList();