--- a/browser/tools/mozscreenshots/head.js
+++ b/browser/tools/mozscreenshots/head.js
@@ -12,16 +12,19 @@ const EXTENSION_DIR = "chrome://mochites
 
 let TestRunner;
 
 async function setup() {
   // This timeout doesn't actually end the job even if it is hit - the buildbot timeout will
   // handle things for us if the test actually hangs.
   requestLongerTimeout(100);
 
+  // Generate output so mozprocess knows we're still alive for the long session.
+  SimpleTest.requestCompleteLog();
+
   info("installing extension temporarily");
   let chromeURL = Services.io.newURI(EXTENSION_DIR);
   let dir = chromeRegistry.convertChromeURL(chromeURL).QueryInterface(Ci.nsIFileURL).file;
   await AddonManager.installTemporaryAddon(dir);
 
   info("Checking for mozscreenshots extension");
   return new Promise((resolve) => {
     AddonManager.getAddonByID("mozscreenshots@mozilla.org", (aAddon) => {

--- a/browser/tools/mozscreenshots/primaryUI/browser_primaryUI.js
+++ b/browser/tools/mozscreenshots/primaryUI/browser_primaryUI.js
@@ -6,15 +6,11 @@
 
 "use strict";
 
 add_task(async function capture() {
   if (!shouldCapture()) {
     return;
   }
 
-  if (AppConstants.platform == "macosx") {
-    // Bug 1425394 - Generate output so mozprocess knows we're still alive for the long session.
-    SimpleTest.requestCompleteLog();
-  }
   let sets = ["TabsInTitlebar", "Tabs", "WindowSize", "Toolbars", "LightweightThemes", "UIDensities"];
   await TestRunner.start(sets, "primaryUI");
 });