diff --git a/app/win/installer/customLocale.nsh b/app/win/installer/customLocale.nsh
index 2684546358..b1db96d3b7 100644
Binary files a/app/win/installer/customLocale.nsh and b/app/win/installer/customLocale.nsh differ
diff --git a/app/win/installer/installer.nsi b/app/win/installer/installer.nsi
index 0502d0f6e7..89d332bfa1 100755
--- a/app/win/installer/installer.nsi
+++ b/app/win/installer/installer.nsi
@@ -606,17 +606,27 @@ FunctionEnd
 Function CheckExistingInstall
   ; If there is a pending file copy from a previous upgrade don't allow
   ; installing until after the system has rebooted.
-  IfFileExists "$INSTDIR\${FileMainEXE}.moz-upgrade" +1 +4
-  MessageBox MB_YESNO|MB_ICONEXCLAMATION "$(WARN_RESTART_REQUIRED_UPGRADE)" IDNO +2
+  IfFileExists "$INSTDIR\${FileMainEXE}.moz-upgrade" +1 +5
+  MessageBox MB_YESNOCANCEL|MB_ICONEXCLAMATION "$(WARN_RESTART_REQUIRED_UPGRADE)" IDNO +3 IDCANCEL +2
   Reboot
   Quit
+  RMDir /r $INSTDIR
+
+  IfFileExists "$INSTDIR\${FileMainEXE}.moz-upgrade" +1 +3
+  MessageBox MB_OK|MB_ICONEXCLAMATION "Failed to remove the previous installation. Please delete $INSTDIR and try again."
+  Quit
 
   ; If there is a pending file deletion from a previous uninstall don't allow
   ; installing until after the system has rebooted.
-  IfFileExists "$INSTDIR\${FileMainEXE}.moz-delete" +1 +4
-  MessageBox MB_YESNO|MB_ICONEXCLAMATION "$(WARN_RESTART_REQUIRED_UNINSTALL)" IDNO +2
+  IfFileExists "$INSTDIR\${FileMainEXE}.moz-delete" +1 +5
+  MessageBox MB_YESNOCANCEL|MB_ICONEXCLAMATION "$(WARN_RESTART_REQUIRED_UNINSTALL)" IDNO +3 IDCANCEL +2
   Reboot
   Quit
+  RMDir /r $INSTDIR
+
+  IfFileExists "$INSTDIR\${FileMainEXE}.moz-delete" +1 +3
+  MessageBox MB_OK|MB_ICONEXCLAMATION "Failed to remove the previous installation. Please delete $INSTDIR and try again."
+  Quit
 
   ${If} ${FileExists} "$INSTDIR\${FileMainEXE}"
     ; Disable the next, cancel, and back buttons