diff --git a/Projects/Compile.pas b/Projects/Compile.pas
index 93043ed5c..3c5a12b4f 100644
--- a/Projects/Compile.pas
+++ b/Projects/Compile.pas
@@ -8336,7 +8336,8 @@ procedure TSetupCompiler.Compile;
 
 
 const
-  BadFileNameChars = '/:*?"<>|';
+  BadFilePathChars = '/*?"<>|';
+  BadFileNameChars = BadFilePathChars + ':';
 var
   SetupE32: TMemoryFile;
   I: Integer;
@@ -8580,7 +8581,7 @@ procedure TSetupCompiler.Compile;
       end else if OutputBaseFileName = 'setup' then
         WarningsList.Add(SCompilerOutputBaseFileNameSetup);
       if (SetupDirectiveLines[ssOutputManifestFile] <> 0) and
-         ((OutputManifestFile = '') or (PathLastDelimiter(BadFileNameChars, OutputManifestFile) <> 0)) then begin
+         ((OutputManifestFile = '') or (PathLastDelimiter(BadFilePathChars, OutputManifestFile) <> 0)) then begin
         LineNumber := SetupDirectiveLines[ssOutputManifestFile];
         AbortCompileOnLineFmt(SCompilerEntryInvalid2, ['Setup', 'OutputManifestFile']);
       end;
diff --git a/build.bat b/build.bat
index d42a3e9f6..22dba885a 100644
--- a/build.bat
+++ b/build.bat
@@ -21,7 +21,7 @@ rem  Once done the 2 installers can be found in Output
 
 setlocal
 
-set VER=5.5.9
+set VER=5.5.10
 
 echo Building Inno Setup %VER%...
 echo.
diff --git a/whatsnew.htm b/whatsnew.htm
index a27f1cd27..e570ac999 100644
--- a/whatsnew.htm
+++ b/whatsnew.htm
@@ -26,6 +26,11 @@
 For conditions of distribution and use, see <a href="http://www.jrsoftware.org/files/is/license.txt">LICENSE.TXT</a>.
 </p>
 
+<p><a name="5.5.10"></a><span class="ver">5.5.10 </span><span class="date">(?)</span></p>
+<ul>
+<li><i>Fix:</i>In 5.5.9 it was no longer possible to include a drive colon in [Setup] section directive <tt>OutputManifestFile</tt>.</li>
+</ul>
+
 <p><a name="5.5.9"></a><span class="ver">5.5.9 </span><span class="date">(2016-04-06)</span></p>
 <ul>
 <li>To <a href="#installerprotect1">further</a> help protect installers against potential <a href="http://msdn.microsoft.com/en-us/library/ff919712.aspx">DLL preloading attacks</a>, Setup/Uninstall now calls SetDefaultDllDirectories if available to remove the application directory from the DLL search order. If SetDefaultDllDirectories is not available or cannot be called, it now additionally preloads a set of system DLLs known to be loaded unsafely by older or unpatched versions of Windows.</li>