diff --git a/clientgui/BOINCGUIApp.cpp b/clientgui/BOINCGUIApp.cpp
index 5593728fcb..097bf04bfe 100644
--- a/clientgui/BOINCGUIApp.cpp
+++ b/clientgui/BOINCGUIApp.cpp
@@ -984,6 +984,9 @@ bool CBOINCGUIApp::SetActiveGUI(int iGUISelection, bool bShowWindow) {
             m_pConfig->Read(wxT("XPos"), &iLeft, 30);
             m_pConfig->Read(wxT("Width"), &iWidth, 800);
             m_pConfig->Read(wxT("Height"), &iHeight, 600);
+            // Guard against a rare situation where registry values are zero
+            if (iWidth < 50) iWidth = 800;
+            if (iHeight < 50) iHeight = 600;
         } else {
             m_pConfig->SetPath(wxT("/Simple"));
             m_pConfig->Read(wxT("YPos"), &iTop, 30);
diff --git a/clientgui/DlgEventLog.cpp b/clientgui/DlgEventLog.cpp
index d1756eb81c..440907a58c 100644
--- a/clientgui/DlgEventLog.cpp
+++ b/clientgui/DlgEventLog.cpp
@@ -763,6 +763,9 @@ void CDlgEventLog::GetWindowDimensions( wxPoint& position, wxSize& size ) {
     pConfig->Read(wxT("Width"), &iWidth, 640);
     pConfig->Read(wxT("Height"), &iHeight, 480);
 
+    // Guard against a rare situation where registry values are zero
+    if (iWidth < 50) iWidth = 640;
+    if (iHeight < 50) iHeight = 480;
     position.y = iTop;
     position.x = iLeft;
     size.x = iWidth;
diff --git a/clientgui/DlgItemProperties.cpp b/clientgui/DlgItemProperties.cpp
index b33e3d784a..bf572a018e 100644
--- a/clientgui/DlgItemProperties.cpp
+++ b/clientgui/DlgItemProperties.cpp
@@ -129,6 +129,10 @@ bool CDlgItemProperties::RestoreState() {
     pConfig->Read(wxT("Width"), &iWidth, wxDefaultCoord);
     pConfig->Read(wxT("Height"), &iHeight, wxDefaultCoord);
 
+    // Guard against a rare situation where registry values are zero
+    if ((iWidth < 50) && (iWidth != wxDefaultCoord)) iWidth = wxDefaultCoord;
+    if ((iHeight < 50) && (iHeight != wxDefaultCoord)) iHeight = wxDefaultCoord;
+
 #ifndef __WXMAC__
     // Set size to saved values or defaults if no saved values
     SetSize(iWidth, iHeight);    
diff --git a/clientgui/sg_DlgMessages.cpp b/clientgui/sg_DlgMessages.cpp
index 5c3f15cc65..f9b584f614 100644
--- a/clientgui/sg_DlgMessages.cpp
+++ b/clientgui/sg_DlgMessages.cpp
@@ -597,6 +597,10 @@ void CDlgMessages::RestoreWindowDimensions() {
     pConfig->Read(wxT("WindowIconized"), &bWindowIconized, false);
     pConfig->Read(wxT("WindowMaximized"), &bWindowMaximized, false);
 
+    // Guard against a rare situation where registry values are zero
+    if (iWidth < 50) iWidth = 640;
+    if (iHeight < 50) iHeight = 480;
+
 #ifndef __WXMAC__
 
     // If either co-ordinate is less then 0 then set it equal to 0 to ensure