diff --git a/browser/installer/windows/nsis/uninstaller.nsi b/browser/installer/windows/nsis/uninstaller.nsi
index 909d0920e32..109945e3771 100755
--- a/browser/installer/windows/nsis/uninstaller.nsi
+++ b/browser/installer/windows/nsis/uninstaller.nsi
@@ -104,6 +104,7 @@ VIAddVersionKey "FileDescription" "${BrandShortName} Helper"
 !insertmacro RegCleanAppHandler
 !insertmacro RegCleanMain
 !insertmacro RegCleanUninstall
+!insertmacro SetBrandNameVars
 !insertmacro UnloadUAC
 !insertmacro WriteRegDWORD2
 !insertmacro WriteRegStr2
diff --git a/toolkit/mozapps/installer/windows/nsis/common.nsh b/toolkit/mozapps/installer/windows/nsis/common.nsh
index 94cad2ba539..1535ce72121 100755
--- a/toolkit/mozapps/installer/windows/nsis/common.nsh
+++ b/toolkit/mozapps/installer/windows/nsis/common.nsh
@@ -4441,6 +4441,10 @@
     !define UninstallOnInitCommon "!insertmacro UninstallOnInitCommonCall"
 
     Function UninstallOnInitCommon
+; Prevents breaking Thunderbird
+!ifdef SetBrandNameVars
+      ${SetBrandNameVars} "$EXEDIR\distribution\setup.ini"
+!endif
 
       ; Prevent launching the application when a reboot is required and this
       ; executable is the main application executable
@@ -4454,6 +4458,11 @@
       IfFileExists "$INSTDIR\${FileMainEXE}" +2 +1
       Quit ; Nothing initialized so no need to call OnEndCommon
 
+; Prevents breaking Thunderbird
+!ifdef SetBrandNameVars
+      ${SetBrandNameVars} "$INSTDIR\distribution\setup.ini"
+!endif
+
       ; Prevent all operations (e.g. set as default, postupdate, etc.) when a
       ; reboot is required and the executable launched is helper.exe
       IfFileExists "$INSTDIR\${FileMainEXE}.moz-upgrade" +1 +4