Index: Main.pas
===================================================================
--- Main.pas	(revision 180)
+++ Main.pas	(working copy)
@@ -25,11 +25,13 @@
     FInnoDBLogFileSize: WideString;
     FInnoDBDataHomeDir: WideString;
     FExistingDataDir: Boolean;
+    FRegPath: WideString;
   public
     constructor Create(ProductName: WideString; Version: WideString; InstallationPath: WideString;
       DataPath: WideString; ExistingDataDir: Boolean; ServiceName: WideString = '';
       CnfFileDestination: WideString = '');
 
+    property RegPath: WideString read FRegPath write FRegPath;      
     property ExistingDataDir: Boolean read FExistingDataDir write FExistingDataDir;
     property ConfigFileDestination: WideString read FConfigFileDestination write FConfigFileDestination;
     property InnoDBLogFileSize: WideString read FInnoDBLogFileSize write FInnoDBLogFileSize;
@@ -1216,6 +1218,8 @@
                     ServerInstance := TServerInstance.Create(SubKeyNames[I], Version, Path, DataPath, UseExistingDataDir);
                     InstanceList.Add(ServerInstance);
                   end;
+
+                  ServerInstance.RegPath := ServiceReg.CurrentPath;
               except
                 // Something is wrong with the reg-entries so continue with next service.
                 Continue;
@@ -2237,6 +2241,7 @@
 
 var
   SuccessCaption: WideString;
+  ServiceReg: TTntRegistry;
 
 begin
   BackBtn.Enabled := False;
@@ -2326,6 +2331,12 @@
         Application.ProcessMessages;
       end;
 
+      // Set the 'FoundExistingDataDir' registry key.
+      ServiceReg := TTntRegistry.Create;
+      if ServiceReg.OpenKey(CurrentInstance.RegPath, False) then
+            ServiceReg.WriteString('FoundExistingDataDir', _('1'));
+      ServiceReg.CloseKey;
+
       SuccessCaption := SuccessCaption+#13#10+
         'Press [Finish] to close the Wizard.';