diff --git a/src/Main/Base/Project/Src/Gui/Dialogs/NewProjectDialog.cs b/src/Main/Base/Project/Src/Gui/Dialogs/NewProjectDialog.cs
index 7cceb5e0fd..8015b32e30 100644
--- a/src/Main/Base/Project/Src/Gui/Dialogs/NewProjectDialog.cs
+++ b/src/Main/Base/Project/Src/Gui/Dialogs/NewProjectDialog.cs
@@ -288,8 +288,8 @@ namespace ICSharpCode.SharpDevelop.Project.Dialogs
 			if (name.Length == 0 || !char.IsLetter(name[0]) && name[0] != '_') {
 				return "${res:ICSharpCode.SharpDevelop.Gui.Dialogs.NewProjectDialog.ProjectNameMustStartWithLetter}";
 			}
-			if (!FileUtility.IsValidDirectoryName(solution)
-			    || !FileUtility.IsValidDirectoryName(name))
+			if (!FileUtility.IsValidDirectoryEntryName(solution)
+			    || !FileUtility.IsValidDirectoryEntryName(name))
 			{
 				return "${res:ICSharpCode.SharpDevelop.Gui.Dialogs.NewProjectDialog.IllegalProjectNameError}";
 			}
diff --git a/src/Main/Base/Project/Src/Gui/Dialogs/SolutionConfiguration/EditAvailableConfigurationsDialog.cs b/src/Main/Base/Project/Src/Gui/Dialogs/SolutionConfiguration/EditAvailableConfigurationsDialog.cs
index fcd9219bfd..c8a36349be 100644
--- a/src/Main/Base/Project/Src/Gui/Dialogs/SolutionConfiguration/EditAvailableConfigurationsDialog.cs
+++ b/src/Main/Base/Project/Src/Gui/Dialogs/SolutionConfiguration/EditAvailableConfigurationsDialog.cs
@@ -182,7 +182,7 @@ namespace ICSharpCode.SharpDevelop.Gui
 				}
 			}
 			if (MSBuildInternals.Escape(newName) != newName
-			    || !FileUtility.IsValidDirectoryName(newName)
+			    || !FileUtility.IsValidDirectoryEntryName(newName)
 			    || newName.Contains("'"))
 			{
 				MessageService.ShowMessage("${res:Dialog.EditAvailableConfigurationsDialog.InvalidName}");
diff --git a/src/Main/Base/Project/Src/Gui/Pads/ProjectBrowser/TreeNodes/DirectoryNode.cs b/src/Main/Base/Project/Src/Gui/Pads/ProjectBrowser/TreeNodes/DirectoryNode.cs
index 5033968ed2..2632bd66d7 100644
--- a/src/Main/Base/Project/Src/Gui/Pads/ProjectBrowser/TreeNodes/DirectoryNode.cs
+++ b/src/Main/Base/Project/Src/Gui/Pads/ProjectBrowser/TreeNodes/DirectoryNode.cs
@@ -478,10 +478,7 @@ namespace ICSharpCode.SharpDevelop.Project
 			if (newName == null) {
 				return;
 			}
-			if (!FileService.CheckFileName(newName)) {
-				return;
-			}
-			if (!FileService.CheckDirectoryName(newName)) {
+			if (!FileService.CheckDirectoryEntryName(newName)) {
 				return;
 			}
 			if (String.Compare(Text, newName, true) == 0) {
diff --git a/src/Main/Base/Project/Src/Gui/Pads/ProjectBrowser/TreeNodes/FileNode.cs b/src/Main/Base/Project/Src/Gui/Pads/ProjectBrowser/TreeNodes/FileNode.cs
index fdf4697497..dd7c29101f 100644
--- a/src/Main/Base/Project/Src/Gui/Pads/ProjectBrowser/TreeNodes/FileNode.cs
+++ b/src/Main/Base/Project/Src/Gui/Pads/ProjectBrowser/TreeNodes/FileNode.cs
@@ -139,7 +139,7 @@ namespace ICSharpCode.SharpDevelop.Project
 			if (newName == null) {
 				return;
 			}
-			if (!FileService.CheckFileName(newName)) {
+			if (!FileService.CheckDirectoryEntryName(newName)) {
 				return;
 			}
 			string oldFileName = FileName;
diff --git a/src/Main/Base/Project/Src/Services/File/FileService.cs b/src/Main/Base/Project/Src/Services/File/FileService.cs
index 2771fa0fc6..6e4e12df40 100644
--- a/src/Main/Base/Project/Src/Services/File/FileService.cs
+++ b/src/Main/Base/Project/Src/Services/File/FileService.cs
@@ -148,29 +148,39 @@ namespace ICSharpCode.SharpDevelop
 		#endregion
 		
 		/// <summary>
-		/// Checks if the file name is valid <b>and shows a MessageBox if it is not valid</b>.
+		/// Checks if the path is valid <b>and shows a MessageBox if it is not valid</b>.
 		/// Do not use in non-UI methods.
 		/// </summary>
-		public static bool CheckFileName(string fileName)
+		public static bool CheckFileName(string path)
 		{
-			if (FileUtility.IsValidPath(fileName))
+			if (FileUtility.IsValidPath(path))
 				return true;
-			MessageService.ShowMessage(StringParser.Parse("${res:ICSharpCode.SharpDevelop.Commands.SaveFile.InvalidFileNameError}", new string[,] {{"FileName", fileName}}));
+			MessageService.ShowMessage(StringParser.Parse("${res:ICSharpCode.SharpDevelop.Commands.SaveFile.InvalidFileNameError}", new string[,] {{"FileName", path}}));
 			return false;
 		}
 		
 		/// <summary>
-		/// Checks that a single directory name is valid.
+		/// Checks that a single directory entry (file or subdirectory) name is valid.
 		/// </summary>
-		/// <param name="name">A single directory name not the full path</param>
-		public static bool CheckDirectoryName(string name)
+		/// <param name="name">A single file name not the full path</param>
+		public static bool CheckDirectoryEntryName(string name)
 		{
-			if (FileUtility.IsValidDirectoryName(name))
+			if (FileUtility.IsValidDirectoryEntryName(name))
 				return true;
 			MessageService.ShowMessage(StringParser.Parse("${res:ICSharpCode.SharpDevelop.Commands.SaveFile.InvalidFileNameError}", new string[,] {{"FileName", name}}));
 			return false;
 		}
 		
+		/// <summary>
+		/// Checks that a single directory name is valid.
+		/// </summary>
+		/// <param name="name">A single directory name not the full path</param>
+		[Obsolete("Use CheckDirectoryEntryName instead")]
+		public static bool CheckDirectoryName(string name)
+		{
+			return CheckDirectoryEntryName(name);
+		}
+		
 		internal sealed class LoadFileWrapper
 		{
 			readonly IDisplayBinding binding;
diff --git a/src/Main/Core/Project/Src/Services/FileUtility/FileUtility.cs b/src/Main/Core/Project/Src/Services/FileUtility/FileUtility.cs
index 4d4ff73e19..8852a72f7a 100644
--- a/src/Main/Core/Project/Src/Services/FileUtility/FileUtility.cs
+++ b/src/Main/Core/Project/Src/Services/FileUtility/FileUtility.cs
@@ -428,12 +428,21 @@ namespace ICSharpCode.Core
 		/// <summary>
 		/// Checks that a single directory name (not the full path) is valid.
 		/// </summary>
+		[ObsoleteAttribute("Use IsValidDirectoryEntryName instead")]
 		public static bool IsValidDirectoryName(string name)
+		{
+			return IsValidDirectoryEntryName(name);
+		}
+		
+		/// <summary>
+		/// Checks that a single directory name (not the full path) is valid.
+		/// </summary>
+		public static bool IsValidDirectoryEntryName(string name)
 		{
 			if (!IsValidPath(name)) {
 				return false;
 			}
-			if (name.IndexOfAny(new char[]{Path.AltDirectorySeparatorChar, Path.DirectorySeparatorChar}) >= 0) {
+			if (name.IndexOfAny(new char[]{Path.AltDirectorySeparatorChar, Path.DirectorySeparatorChar,Path.VolumeSeparatorChar}) >= 0) {
 				return false;
 			}
 			if (name.Trim(' ').Length == 0) {