--- a/browser/components/preferences/in-content/privacy.js
+++ b/browser/components/preferences/in-content/privacy.js
@@ -1081,44 +1081,52 @@ var gPrivacyPane = {
     let blockUnwantedPref = document.getElementById("browser.safebrowsing.downloads.remote.block_potentially_unwanted");
     let blockUncommonPref = document.getElementById("browser.safebrowsing.downloads.remote.block_uncommon");
 
     enableSafeBrowsing.addEventListener("command", function() {
       safeBrowsingPhishingPref.value = enableSafeBrowsing.checked;
       safeBrowsingMalwarePref.value = enableSafeBrowsing.checked;
 
       if (enableSafeBrowsing.checked) {
-        blockDownloads.removeAttribute("disabled");
-        if (blockDownloads.checked) {
+        if (blockDownloads) {
+          blockDownloads.removeAttribute("disabled");
+          if (blockDownloads.checked) {
+            blockUncommonUnwanted.removeAttribute("disabled");
+          }
+        } else {
           blockUncommonUnwanted.removeAttribute("disabled");
         }
       } else {
-        blockDownloads.setAttribute("disabled", "true");
+        if (blockDownloads) {
+          blockDownloads.setAttribute("disabled", "true");
+        }
         blockUncommonUnwanted.setAttribute("disabled", "true");
       }
     });
 
-    blockDownloads.addEventListener("command", function() {
-      blockDownloadsPref.value = blockDownloads.checked;
-      if (blockDownloads.checked) {
-        blockUncommonUnwanted.removeAttribute("disabled");
-      } else {
-        blockUncommonUnwanted.setAttribute("disabled", "true");
-      }
-    });
+    if (blockDownloads) {
+      blockDownloads.addEventListener("command", function() {
+        blockDownloadsPref.value = blockDownloads.checked;
+        if (blockDownloads.checked) {
+          blockUncommonUnwanted.removeAttribute("disabled");
+        } else {
+          blockUncommonUnwanted.setAttribute("disabled", "true");
+        }
+      });
+    }
 
     blockUncommonUnwanted.addEventListener("command", function() {
       blockUnwantedPref.value = blockUncommonUnwanted.checked;
       blockUncommonPref.value = blockUncommonUnwanted.checked;
 
       let malware = malwareTable.value
         .split(",")
         .filter(x => x !== "goog-unwanted-proto" &&
-          x !== "goog-unwanted-shavar" &&
-          x !== "test-unwanted-simple");
+                     x !== "goog-unwanted-shavar" &&
+                     x !== "test-unwanted-simple");
 
       if (blockUncommonUnwanted.checked) {
         if (malware.indexOf("goog-malware-shavar") != -1) {
           malware.push("goog-unwanted-shavar");
         } else {
           malware.push("goog-unwanted-proto");
         }
 
@@ -1130,23 +1138,28 @@ var gPrivacyPane = {
 
       malwareTable.value = malware.join(",");
     });
 
     // set initial values
 
     enableSafeBrowsing.checked = safeBrowsingPhishingPref.value && safeBrowsingMalwarePref.value;
     if (!enableSafeBrowsing.checked) {
-      blockDownloads.setAttribute("disabled", "true");
+      if (blockDownloads) {
+        blockDownloads.setAttribute("disabled", "true");
+      }
+
       blockUncommonUnwanted.setAttribute("disabled", "true");
     }
 
-    blockDownloads.checked = blockDownloadsPref.value;
-    if (!blockDownloadsPref.value) {
-      blockUncommonUnwanted.setAttribute("disabled", "true");
+    if (blockDownloads) {
+      blockDownloads.checked = blockDownloadsPref.value;
+      if (!blockDownloadsPref.value) {
+        blockUncommonUnwanted.setAttribute("disabled", "true");
+      }
     }
 
     blockUncommonUnwanted.checked = blockUnwantedPref.value && blockUncommonPref.value;
   },
 
   /**
    * Displays the exceptions lists for add-on installation warnings.
    */

--- a/browser/components/preferences/in-content/privacy.xul
+++ b/browser/components/preferences/in-content/privacy.xul
@@ -727,19 +727,21 @@
 
 <!-- addons, forgery (phishing) UI Security -->
 <groupbox id="addonsPhishingGroup" data-category="panePrivacy" hidden="true">
   <caption><label>&phishingProtection.label;</label></caption>
   <checkbox id="enableSafeBrowsing"
             label="&enableSafeBrowsing.label;"
             accesskey="&enableSafeBrowsing.accesskey;" />
   <vbox class="indent">
+#ifdef MOZILLA_OFFICIAL
     <checkbox id="blockDownloads"
               label="&blockDownloads.label;"
               accesskey="&blockDownloads.accesskey;" />
+#endif
     <checkbox id="blockUncommonUnwanted"
               label="&blockUncommonAndUnwanted.label;"
               accesskey="&blockUncommonAndUnwanted.accesskey;" />
   </vbox>
 </groupbox>
 
 <!-- Certificates -->
 <groupbox id="certSelection" data-category="panePrivacy" hidden="true">

--- a/browser/components/preferences/in-content/tests/browser_security-1.js
+++ b/browser/components/preferences/in-content/tests/browser_security-1.js
@@ -35,34 +35,41 @@ add_task(async function() {
     gBrowser.reload();
     await BrowserTestUtils.browserLoaded(gBrowser.selectedBrowser);
 
     let doc = gBrowser.selectedBrowser.contentDocument;
     let checkbox = doc.getElementById("enableSafeBrowsing");
     let blockDownloads = doc.getElementById("blockDownloads");
     let blockUncommon = doc.getElementById("blockUncommonUnwanted");
     let checked = checkbox.checked;
+    if (!AppConstants.MOZILLA_OFFICIAL) {
+      is(blockDownloads, undefined, "downloads protection is disabled in un-official builds");
+    } else {
+      is(blockDownloads.hasAttribute("disabled"), !checked, "block downloads checkbox is set correctly");
+    }
+
     is(checked, val1 && val2, "safebrowsing preference is initialized correctly");
     // should be disabled when checked is false (= pref is turned off)
-    is(blockDownloads.hasAttribute("disabled"), !checked, "block downloads checkbox is set correctly");
     is(blockUncommon.hasAttribute("disabled"), !checked, "block uncommon checkbox is set correctly");
 
     // scroll the checkbox into the viewport and click checkbox
     checkbox.scrollIntoView();
     EventUtils.synthesizeMouseAtCenter(checkbox, {}, gBrowser.selectedBrowser.contentWindow);
 
     // check that both settings are now turned on or off
     is(Services.prefs.getBoolPref("browser.safebrowsing.phishing.enabled"), !checked,
        "safebrowsing.enabled is set correctly");
     is(Services.prefs.getBoolPref("browser.safebrowsing.malware.enabled"), !checked,
        "safebrowsing.malware.enabled is set correctly");
 
     // check if the other checkboxes have updated
     checked = checkbox.checked;
-    is(blockDownloads.hasAttribute("disabled"), !checked, "block downloads checkbox is set correctly");
-    is(blockUncommon.hasAttribute("disabled"), !checked || !blockDownloads.checked, "block uncommon checkbox is set correctly");
+    if (blockDownloads) {
+      is(blockDownloads.hasAttribute("disabled"), !checked, "block downloads checkbox is set correctly");
+      is(blockUncommon.hasAttribute("disabled"), !checked || !blockDownloads.checked, "block uncommon checkbox is set correctly");
+    }
   }
 
   await checkPrefSwitch(true, true);
   await checkPrefSwitch(false, true);
   await checkPrefSwitch(true, false);
   await checkPrefSwitch(false, false);
 });

--- a/browser/components/preferences/in-content/tests/browser_security-2.js
+++ b/browser/components/preferences/in-content/tests/browser_security-2.js
@@ -31,16 +31,21 @@ add_task(async function() {
   async function checkPrefSwitch(val) {
     Services.prefs.setBoolPref("browser.safebrowsing.downloads.enabled", val);
 
     gBrowser.reload();
     await BrowserTestUtils.browserLoaded(gBrowser.selectedBrowser);
 
     let doc = gBrowser.selectedBrowser.contentDocument;
     let checkbox = doc.getElementById("blockDownloads");
+    if (!AppConstants.MOZILLA_OFFICIAL) {
+      is(checkbox, undefined, "downloads protection is disabled in un-official builds");
+      return;
+    }
+
     let blockUncommon = doc.getElementById("blockUncommonUnwanted");
     let checked = checkbox.checked;
     is(checked, val, "downloads preference is initialized correctly");
     // should be disabled when val is false (= pref is turned off)
     is(blockUncommon.hasAttribute("disabled"), !val, "block uncommon checkbox is set correctly");
 
     // scroll the checkbox into view, otherwise the synthesizeMouseAtCenter will be ignored, and click it
     checkbox.scrollIntoView();