diff --git a/src/plugins/projectexplorer/projectexplorer.cpp b/src/plugins/projectexplorer/projectexplorer.cpp
index eae61dd93b120be2310b7d8377ae0459822a5834..a4eba076f30e5bbef6b92c39e49dfd21b26db705 100644
--- a/src/plugins/projectexplorer/projectexplorer.cpp
+++ b/src/plugins/projectexplorer/projectexplorer.cpp
@@ -1297,6 +1297,9 @@ bool ProjectExplorerPlugin::saveModifiedFiles(const QList<Project *> & projects)
     foreach (Project *pro, projects)
         allFiles << allFilesWithDependencies(pro);
 
+    // allFiles must be sorted for the algorithm to work
+    qSort(allFiles);
+
     foreach (Core::IFile * fi, modifiedFi)
         modified.insert(fi->fileName(), fi);