diff --git a/browser/branding/unofficial/branding.nsi b/browser/branding/unofficial/branding.nsi
index 546a03639f8..1426ff4b5d3 100644
--- a/browser/branding/unofficial/branding.nsi
+++ b/browser/branding/unofficial/branding.nsi
@@ -34,17 +34,22 @@
 #
 # ***** END LICENSE BLOCK *****
 
-# NSIS defines for nightly builds.
-# The release build branding.nsi is located in other-license/branding/firefox/
+# 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/
 !define BrandShortName        "Gran Paradiso"
-!define BrandFullName         "Gran Paradiso"
-# BrandFullNameInternal is used for some registry and file system values that
-# should not contain release that may be in the BrandFullName (e.g. Beta 1, etc.)
+# BrandFullNameInternal is used for some registry and file system values
+# instead of BrandFullName and typically should not be modified.
 !define BrandFullNameInternal "Gran Paradiso"
 !define CompanyName           "mozilla.org"
 !define URLInfoAbout          "http://www.mozilla.org"
 !define URLUpdateInfo         "http://www.mozilla.org/projects/firefox"
 !define SurveyURL             "https://survey.mozilla.com/1/Mozilla%20Firefox/${AppVersion}/${AB_CD}/exit.html"
 
-# Percentage of new "Standard" installs to enable talkback for
-!define RandomPercent         "50"
+# Everything below this line may be modified for Alpha / Beta releases.
+!define BrandFullName         "Gran Paradiso"
+
+# Add !define NO_INSTDIR_FROM_REG to prevent finding a non-default installation
+# directory in the registry and using that as the default. This prevents
+# Beta releases built with official branding from finding an existing install
+# of an official release and defaulting to its installation directory.
diff --git a/browser/installer/windows/nsis/branding.nsi b/browser/installer/windows/nsis/branding.nsi
index 6a6bb78367b..8c378e58ded 100644
--- a/browser/installer/windows/nsis/branding.nsi
+++ b/browser/installer/windows/nsis/branding.nsi
@@ -34,17 +34,22 @@
 #
 # ***** END LICENSE BLOCK *****
 
-# NSIS defines for nightly builds.
-# The release build branding.nsi is located in other-license/branding/firefox/
+# NSIS branding defines for nightly 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/
 !define BrandShortName        "Minefield"
-!define BrandFullName         "Minefield"
-# BrandFullNameInternal is used for some registry and file system values that
-# should not contain release that may be in the BrandFullName (e.g. Beta 1, etc.)
+# BrandFullNameInternal is used for some registry and file system values
+# instead of BrandFullName and typically should not be modified.
 !define BrandFullNameInternal "Minefield"
 !define CompanyName           "mozilla.org"
 !define URLInfoAbout          "http://www.mozilla.org"
 !define URLUpdateInfo         "http://www.mozilla.org/projects/firefox"
 !define SurveyURL             "https://survey.mozilla.com/1/Mozilla%20Firefox/${AppVersion}/${AB_CD}/exit.html"
 
-# Percentage of new "Standard" installs to enable talkback for
-!define RandomPercent         "50"
+# Everything below this line may be modified for Alpha / Beta releases.
+!define BrandFullName         "Minefield"
+
+# Add !define NO_INSTDIR_FROM_REG to prevent finding a non-default installation
+# directory in the registry and using that as the default. This prevents
+# Beta releases built with official branding from finding an existing install
+# of an official release and defaulting to its installation directory.
diff --git a/other-licenses/branding/firefox/branding.nsi b/other-licenses/branding/firefox/branding.nsi
index 07af954363a..f0065cdcc75 100755
--- a/other-licenses/branding/firefox/branding.nsi
+++ b/other-licenses/branding/firefox/branding.nsi
@@ -34,17 +34,22 @@
 #
 # ***** END LICENSE BLOCK *****
 
-# NSIS defines for release builds.
+# 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/
 !define BrandShortName        "Firefox"
-!define BrandFullName         "Mozilla Firefox"
-# BrandFullNameInternal is used for some registry and file system values that
-# should not contain release that may be in the BrandFullName (e.g. Beta 1, etc.)
+# BrandFullNameInternal is used for some registry and file system values
+# instead of BrandFullName and typically should not be modified.
 !define BrandFullNameInternal "Mozilla Firefox"
 !define CompanyName           "Mozilla Corporation"
 !define URLInfoAbout          "http://${AB_CD}.www.mozilla.com/${AB_CD}/"
 !define URLUpdateInfo         "http://${AB_CD}.www.mozilla.com/${AB_CD}/firefox/"
 !define SurveyURL             "https://survey.mozilla.com/1/Mozilla%20Firefox/${AppVersion}/${AB_CD}/exit.html"
 
-# Percentage of new "Standard" installs to enable talkback for
-!define RandomPercent         "10"
+# Everything below this line may be modified for Alpha / Beta releases.
+!define BrandFullName         "Mozilla Firefox"
+
+# Add !define NO_INSTDIR_FROM_REG to prevent finding a non-default installation
+# directory in the registry and using that as the default. This prevents
+# Beta releases built with official branding from finding an existing install
+# of an official release and defaulting to its installation directory.
diff --git a/toolkit/mozapps/installer/windows/nsis/common.nsh b/toolkit/mozapps/installer/windows/nsis/common.nsh
index af7dcec9b84..b32cf09c8a8 100755
--- a/toolkit/mozapps/installer/windows/nsis/common.nsh
+++ b/toolkit/mozapps/installer/windows/nsis/common.nsh
@@ -4261,7 +4261,10 @@
     !insertmacro CanWriteToInstallDir
     !insertmacro CheckDiskSpace
     !insertmacro GetLongPath
+
+!ifndef NO_INSTDIR_FROM_REG
     !insertmacro GetSingleInstallPath
+!endif
 
     !verbose push
     !verbose ${_MOZFUNC_VERBOSE}
@@ -4270,6 +4273,7 @@
     Function PreDirectoryCommon
       Push $R9
 
+!ifndef NO_INSTDIR_FROM_REG
       SetShellVarContext all      ; Set SHCTX to HKLM
       ${GetSingleInstallPath} "Software\Mozilla\${BrandFullNameInternal}" $R9
 
@@ -4281,6 +4285,7 @@
       fix_install_dir:
       StrCmp "$R9" "false" +2 +1
       StrCpy $INSTDIR "$R9"
+!endif
 
       IfFileExists "$INSTDIR" +1 check_install_dir