diff --git a/pcbnew/files.cpp b/pcbnew/files.cpp
index 939fe4830d..d151b9534c 100644
--- a/pcbnew/files.cpp
+++ b/pcbnew/files.cpp
@@ -408,8 +408,6 @@ bool PCB_EDIT_FRAME::OpenProjectFiles( const std::vector<wxString>& aFileSet, in
         return false;
     }
 
-    m_file_checker.reset( lockFile.release() );
-
     if( GetScreen()->IsModify() && !GetBoard()->IsEmpty() )
     {
         if( !HandleUnsavedChanges( this, _( "The current PCB has been modified.  Save changes?" ),
@@ -419,6 +417,9 @@ bool PCB_EDIT_FRAME::OpenProjectFiles( const std::vector<wxString>& aFileSet, in
         }
     }
 
+    // Release the lock file, until the new file is actually loaded
+    m_file_checker.reset( nullptr );
+
     wxFileName pro = fullFileName;
     pro.SetExt( ProjectFileExtension );
 
@@ -503,6 +504,7 @@ bool PCB_EDIT_FRAME::OpenProjectFiles( const std::vector<wxString>& aFileSet, in
             return false;
         }
 
+
         // 6.0 TODO: some settings didn't make it into the board file in 5.1 so as not to
         // change the file format.  For 5.1 we must copy them across from the config-initialized
         // board.
@@ -552,6 +554,9 @@ bool PCB_EDIT_FRAME::OpenProjectFiles( const std::vector<wxString>& aFileSet, in
         GetBoard()->SetFileName( fname );
     }
 
+    // Lock the file newly opened:
+    m_file_checker.reset( lockFile.release() );
+
     if( !converted )
         UpdateFileHistory( GetBoard()->GetFileName() );