--- a/browser/branding/aurora/branding.nsi
+++ b/browser/branding/aurora/branding.nsi
@@ -5,16 +5,17 @@
 # NSIS branding defines for Developer Edition builds.
 # The official release build branding.nsi is located in other-license/branding/firefox/
 # The unofficial build branding.nsi is located in browser/branding/unofficial/
 
 # BrandFullNameInternal is used for some registry and file system values
 # instead of BrandFullName and typically should not be modified.
 !define BrandFullNameInternal "Firefox Developer Edition"
 !define BrandShortName        "Firefox Developer Edition"
+!define BrandFullName         "Firefox Developer Edition"
 !define CompanyName           "mozilla.org"
 !define URLInfoAbout          "https://www.mozilla.org"
 !define HelpLink              "https://support.mozilla.org"
 
 !define URLStubDownload32 "http://download.mozilla.org/?os=win&lang=${AB_CD}&product=firefox-devedition-latest"
 !define URLStubDownload64 "http://download.mozilla.org/?os=win64&lang=${AB_CD}&product=firefox-devedition-latest"
 !define URLManualDownload "https://www.mozilla.org/${AB_CD}/firefox/installer-help/?channel=aurora&installer_lang=${AB_CD}"
 !define URLSystemRequirements "https://www.mozilla.org/firefox/system-requirements/"

--- a/browser/branding/official/branding.nsi
+++ b/browser/branding/official/branding.nsi
@@ -4,16 +4,17 @@
 
 # NSIS branding defines for official release builds.
 # The nightly build branding.nsi is located in browser/installer/windows/nsis/
 # The unofficial build branding.nsi is located in browser/branding/unofficial/
 
 # BrandFullNameInternal is used for some registry and file system values
 # instead of BrandFullName and typically should not be modified.
 !define BrandFullNameInternal "Mozilla Firefox"
+!define BrandFullName         "Mozilla Firefox"
 !define CompanyName           "Mozilla Corporation"
 !define URLInfoAbout          "https://www.mozilla.org"
 !define URLUpdateInfo         "https://www.mozilla.org/firefox/${AppVersion}/releasenotes"
 !define HelpLink              "https://support.mozilla.org"
 
 ; The OFFICIAL define is a workaround to support different urls for Release and
 ; Beta since they share the same branding when building with other branches that
 ; set the update channel to beta.

--- a/browser/branding/unofficial/branding.nsi
+++ b/browser/branding/unofficial/branding.nsi
@@ -4,16 +4,17 @@
 
 # NSIS branding defines for unofficial builds.
 # The official release build branding.nsi is located in other-license/branding/firefox/
 # The nightly build branding.nsi is located in browser/installer/windows/nsis/
 
 # BrandFullNameInternal is used for some registry and file system values
 # instead of BrandFullName and typically should not be modified.
 !define BrandFullNameInternal "Mozilla Developer Preview"
+!define BrandFullName         "Mozilla Developer Preview"
 !define CompanyName           "mozilla.org"
 !define URLInfoAbout          "https://www.mozilla.org"
 !define HelpLink              "https://support.mozilla.org"
 
 !define URLStubDownload32 "http://download.mozilla.org/?os=win&lang=${AB_CD}&product=firefox-latest"
 !define URLStubDownload64 "http://download.mozilla.org/?os=win64&lang=${AB_CD}&product=firefox-latest"
 !define URLManualDownload "https://www.mozilla.org/${AB_CD}/firefox/installer-help/?channel=release&installer_lang=${AB_CD}"
 !define URLSystemRequirements "https://www.mozilla.org/firefox/system-requirements/"

--- a/browser/installer/windows/nsis/defines.nsi.in
+++ b/browser/installer/windows/nsis/defines.nsi.in
@@ -31,17 +31,19 @@
 !define MainWindowClass       "MozillaWindowClass"
 !define DialogWindowClass     "MozillaDialogClass"
 !define DDEApplication        "Firefox"
 !define AppRegName            "Firefox"
 
 !ifndef DEV_EDITION
 !define BrandShortName        "@MOZ_APP_DISPLAYNAME@"
 !endif
+!ifndef BrandFullName
 !define BrandFullName         "${BrandFullNameInternal}"
+!endif
 
 !define CERTIFICATE_NAME            "Mozilla Corporation"
 !define CERTIFICATE_ISSUER          "DigiCert SHA2 Assured ID Code Signing CA"
 ; Changing the name or issuer requires us to have both the old and the new
 ;  in the registry at the same time, temporarily.
 !define CERTIFICATE_NAME_PREVIOUS   "Mozilla Corporation"
 !define CERTIFICATE_ISSUER_PREVIOUS "DigiCert Assured ID Code Signing CA-1"
 

--- a/browser/installer/windows/nsis/maintenanceservice_installer.nsi
+++ b/browser/installer/windows/nsis/maintenanceservice_installer.nsi
@@ -46,17 +46,19 @@ Var BrandFullName
 !define CompanyName "Mozilla Corporation"
 !define BrandFullNameInternal ""
 
 ; The following includes are custom.
 !include defines.nsi
 ; We keep defines.nsi defined so that we get other things like 
 ; the version number, but we redefine BrandFullName
 !define MaintFullName "Mozilla Maintenance Service"
+!ifdef BrandFullName
 !undef BrandFullName
+!endif
 !define BrandFullName "${MaintFullName}"
 
 !include common.nsh
 !include locales.nsi
 
 VIAddVersionKey "FileDescription" "${MaintFullName} Installer"
 VIAddVersionKey "OriginalFilename" "maintenanceservice_installer.exe"
 

--- a/toolkit/components/maintenanceservice/bootstrapinstaller/maintenanceservice_installer.nsi
+++ b/toolkit/components/maintenanceservice/bootstrapinstaller/maintenanceservice_installer.nsi
@@ -46,17 +46,19 @@ Var BrandFullName
 !define CompanyName "Mozilla Corporation"
 !define BrandFullNameInternal ""
 
 ; The following includes are custom.
 !include defines.nsi
 ; We keep defines.nsi defined so that we get other things like 
 ; the version number, but we redefine BrandFullName
 !define MaintFullName "Mozilla Maintenance Service"
+!ifdef BrandFullName
 !undef BrandFullName
+!endif
 !define BrandFullName "${MaintFullName}"
 
 !include common.nsh
 !include locales.nsi
 
 VIAddVersionKey "FileDescription" "${MaintFullName} Installer"
 VIAddVersionKey "OriginalFilename" "maintenanceservice_installer.exe"