diff -uNr qt3.orig/src/dialogs/qfiledialog.cpp qt3/src/dialogs/qfiledialog.cpp
--- qt3.orig/src/dialogs/qfiledialog.cpp	2005-09-30 17:58:32.000000000 +0200
+++ qt3/src/dialogs/qfiledialog.cpp	2006-10-07 22:54:36.000000000 +0200
@@ -5732,6 +5732,17 @@
      QString p = QDir::convertSeparators(u.path());
      if(p.contains(':') == 1)
 	return TRUE;
+#elif defined(Q_OS_CYGWIN)
+     QString p = u.path();
+     if ( p == "/" )
+	 return TRUE;
+     if ( p[0] == '/' && p[1] == '/' ) {
+	 int slashes = p.contains( '/' );
+	 if ( slashes <= 2 )
+	     return TRUE;
+	 if ( slashes == 3 && p[ (int)p.length() - 1 ] == '/' )
+	     return TRUE;
+     }
 #elif defined(Q_OS_UNIX)
     if ( u.path() == "/" )
 	return TRUE;
diff -uNr qt3.orig/src/kernel/qurl.cpp qt3/src/kernel/qurl.cpp
--- qt3.orig/src/kernel/qurl.cpp	2006-02-16 04:23:44.000000000 +0100
+++ qt3/src/kernel/qurl.cpp	2006-10-07 22:56:36.000000000 +0200
@@ -833,7 +833,7 @@
     if ( !d->host.isEmpty() && d->host[ 0 ] == '@' )
 	d->host.remove( (uint)0, 1 );
 
-#if defined(Q_OS_WIN32)
+#if defined(Q_OS_WIN32) || defined (Q_OS_CYGWIN)
     // hack for windows file://machine/path syntax
     if ( d->protocol == "file" ) {
 	if ( url.left( 7 ) == "file://" &&
@@ -1027,7 +1027,7 @@
 	if ( QDir::isRelativePath( d->path ) ) {
 	    d->cleanPath = d->path;
 	} else if ( isLocalFile() ) {
-#if defined(Q_OS_WIN32)
+#if defined(Q_OS_WIN32) || defined(Q_OS_CYGWIN)
 	    // hack for stuff like \\machine\path and //machine/path on windows
 	    if ( ( d->path.left( 1 ) == "/" || d->path.left( 1 ) == "\\" ) &&
 		 d->path.length() > 1 ) {
diff -uNr qt3.orig/src/tools/qdir.cpp qt3/src/tools/qdir.cpp
--- qt3.orig/src/tools/qdir.cpp	2006-02-15 19:26:24.000000000 +0100
+++ qt3/src/tools/qdir.cpp	2006-10-07 23:00:02.000000000 +0200
@@ -1293,6 +1293,9 @@
 	} else {
 	    newPath = name.left(2) + newPath;
 	}
+#elif defined(Q_OS_CYGWIN)
+	if ( name[0] == '/' && name[1] == '/' ) // "//machine/x/ ..."
+	    newPath.insert( 0, '/' );
 #endif
     }
     return newPath;