--- a/devtools/client/debugger/test/mochitest/browser2.ini
+++ b/devtools/client/debugger/test/mochitest/browser2.ini
@@ -303,25 +303,25 @@ skip-if = e10s && debug
 [browser_dbg_sources-webext-contentscript.js]
 [browser_dbg_split-console-paused-reload.js]
 skip-if = true # Bug 1288348 - previously e10s && debug
 [browser_dbg_stack-01.js]
 skip-if = e10s && debug
 [browser_dbg_stack-02.js]
 skip-if = e10s && debug
 [browser_dbg_stack-03.js]
-skip-if = e10s # TODO
+skip-if = e10s || (!e10s && os == "win") # TODO, win !e10s: Bug 1391369
 [browser_dbg_stack-04.js]
-skip-if = e10s && debug
+skip-if = e10s && debug || (!e10s && os == "win") # Bug 1391369
 [browser_dbg_stack-05.js]
-skip-if = e10s && (debug || asan) # timeouts
+skip-if = e10s && (debug || asan) || (!e10s && os == "win") # timeouts, Bug 1391369
 [browser_dbg_stack-06.js]
-skip-if = e10s && debug
+skip-if = e10s && debug || (!e10s && os == "win") # Bug 1391369
 [browser_dbg_stack-07.js]
-skip-if = e10s && debug
+skip-if = e10s && debug || (!e10s && os == "win") # Bug 1391369
 [browser_dbg_stack-contextmenu-01.js]
 skip-if = e10s && debug
 [browser_dbg_stack-contextmenu-02.js]
 subsuite = clipboard
 skip-if = (e10s && debug) || (os == 'linux' && bits == 32 && debug) # bug 1328915, disable linux32 debug devtools for timeouts
 [browser_dbg_step-out.js]
 skip-if = e10s && debug
 [browser_dbg_tabactor-01.js]

--- a/dom/base/test/browser.ini
+++ b/dom/base/test/browser.ini
@@ -32,17 +32,17 @@ support-files =
 [browser_bug902350.js]
 tags = mcb
 [browser_bug1011748.js]
 [browser_bug1058164.js]
 [browser_force_process_selector.js]
 skip-if = !e10s # this only makes sense with e10s-multi
 [browser_messagemanager_loadprocessscript.js]
 [browser_aboutnewtab_process_selection.js]
-skip-if = os == 'linux' # Linux x64 JSDCov failure
+skip-if = os == 'linux' || !e10s # Bug 1391363
 [browser_messagemanager_targetframeloader.js]
 [browser_messagemanager_unload.js]
 [browser_pagehide_on_tab_close.js]
 skip-if = e10s # this tests non-e10s behavior. it's not expected to work in e10s.
 [browser_state_notifications.js]
 skip-if = true # Bug 1271028
 [browser_use_counters.js]
 [browser_timeout_throttling_with_audio_playback.js]

--- a/dom/browser-element/mochitest/mochitest-oop.ini
+++ b/dom/browser-element/mochitest/mochitest-oop.ini
@@ -89,13 +89,14 @@ disabled = Disabling some OOP tests for 
 #skip-if = asan # bug 1189592 - should be OK when ASAN mochitests are on Ubuntu 16.04
 disabled = Disabling some OOP tests for WebIDL scope changes (bug 1310706 for re-enabling)
 [test_browserElement_oop_XFrameOptionsDeny.html]
 disabled = Disabling some OOP tests for WebIDL scope changes (bug 1310706 for re-enabling)
 [test_browserElement_oop_XFrameOptionsSameOrigin.html]
 [test_browserElement_oop_ContextmenuEvents.html]
 [test_browserElement_oop_CloseFromOpener.html]
 [test_browserElement_oop_ExposableURI.html]
+skip-if = !e10s # Bug 1391349
 [test_browserElement_oop_GetContentDimensions.html]
 disabled = Disabling some OOP tests for WebIDL scope changes (bug 1310706 for re-enabling)
 [test_browserElement_oop_getWebManifest.html]
 disabled = Disabling some OOP tests for WebIDL scope changes (bug 1310706 for re-enabling)
 [test_browserElement_oop_OpenWindowEmpty.html]

--- a/taskcluster/ci/test/tests.yml
+++ b/taskcluster/ci/test/tests.yml
@@ -116,16 +116,20 @@ crashtest:
         by-test-platform:
             macosx64-stylo.*: ['autoland', 'mozilla-central', 'try']
             default: built-projects
     chunks:
         by-test-platform:
             android-4.3-arm7-api-15/debug: 10
             android.*: 4
             default: 1
+    e10s:
+        by-test-platform:
+            windows7-32/debug: both
+            default: true
     mozharness:
         by-test-platform:
             android.*:
                 script: android_emulator_unittest.py
                 no-read-buildbot-config: true
                 config:
                     - android/androidarm_4_3.py
                 extra-options:
@@ -291,16 +295,21 @@ jsreftest:
         by-test-platform:
             android-4.3-arm7-api-15/debug: 100
             android.*: 40
             windows.*: 2
             linux64-ccov/.*: 5
             linux64-qr/.*: 4
             macosx.*: 2
             default: 3
+    e10s:
+        by-test-platform:
+            linux64-jsdcov/opt: false
+            windows7-32/debug: both
+            default: true
     max-run-time:
         by-test-platform:
             android.*: 7200
             default: 3600
     mozharness:
         by-test-platform:
             android.*:
                 script: android_emulator_unittest.py
@@ -431,16 +440,17 @@ mochitest:
             android.*: 20
             macosx.*: 5
             windows.*: 5
             linux32/debug: 16
             linux.*: 10
     e10s:
         by-test-platform:
             linux64-jsdcov/opt: false
+            windows7-32/debug: both
             default: true
     max-run-time:
         by-test-platform:
             android-4.3-arm7-api-15/debug: 10800
             linux64-jsdcov/opt: 10800
             default: 5400
     allow-software-gl-layers: false
     run-on-projects:
@@ -533,16 +543,17 @@ mochitest-browser-chrome:
             linux64-jsdcov/opt: 35
             linux64/debug: 16
             linux32/debug: 16
             linux64-asan/opt: 16
             default: 7
     e10s:
         by-test-platform:
             linux64-jsdcov/opt: false
+            windows7-32/debug: both
             default: true
     max-run-time:
         by-test-platform:
             linux64-jsdcov/opt: 7200
             linux64-ccov/opt: 7200
             linux64/debug: 5400
             linux32/debug: 5400
             default: 3600
@@ -705,16 +716,20 @@ mochitest-clipboard:
             linux64-stylo.*: ['autoland', 'mozilla-central', 'try']
             macosx64-stylo/.*: ['mozilla-central', 'try']
             default: built-projects
     worker-type:
         by-test-platform:
             windows7-32.*: buildbot-bridge/buildbot-bridge
             windows8-64.*: buildbot-bridge/buildbot-bridge
             default: null
+    e10s:
+        by-test-platform:
+            windows7-32/debug: both
+            default: true
     mozharness:
         by-test-platform:
             android.*:
                 mochitest-flavor: plain
                 script: android_emulator_unittest.py
                 no-read-buildbot-config: true
                 config:
                     - android/androidarm_4_3.py
@@ -762,16 +777,17 @@ mochitest-devtools-chrome:
         by-test-platform:
             linux64-stylo.*: ['autoland', 'mozilla-central', 'try']
             macosx64-stylo/.*: ['mozilla-central', 'try']
             windows7-32-stylo.*: ['autoland', 'mozilla-central', 'try']
             default: built-projects
     e10s:
         by-test-platform:
             linux64-jsdcov/opt: false
+            windows7-32/debug: both
             default: true
     mozharness:
         mochitest-flavor: chrome
         script: desktop_unittest.py
         no-read-buildbot-config: true
         chunked: true
         config:
             by-test-platform:
@@ -811,16 +827,20 @@ mochitest-gpu:
             linux64-stylo.*: ['autoland', 'mozilla-central', 'try']
             macosx64-stylo/.*: ['mozilla-central', 'try']
             windows7-32-stylo.*: ['autoland', 'mozilla-central', 'try']
             default: built-projects
     worker-type:
         by-test-platform:
             windows8-64.*: buildbot-bridge/buildbot-bridge
             default: null
+    e10s:
+        by-test-platform:
+            windows7-32/debug: both
+            default: true
     mozharness:
         by-test-platform:
             android.*:
                 mochitest-flavor: plain
                 script: android_emulator_unittest.py
                 no-read-buildbot-config: true
                 config:
                     - android/androidarm_4_3.py
@@ -851,17 +871,16 @@ mochitest-gpu:
 
 mochitest-jetpack:
     description: "Mochitest jetpack run"
     suite: mochitest/jetpack-package
     treeherder-symbol: tc-M(JP)
     loopback-video: true
     e10s: false
     max-run-time: 5400
-    docker-image: {"in-tree": "desktop1604-test"}
     mozharness:
         mochitest-flavor: jetpack-package
         script: desktop_unittest.py
         no-read-buildbot-config: true
         chunked: false
         config:
             by-test-platform:
                 windows.*:
@@ -987,16 +1006,20 @@ mochitest-webgl:
     worker-type:
         by-test-platform:
             windows8-64.*: buildbot-bridge/buildbot-bridge
             default: null
     chunks:
         by-test-platform:
             android.*: 10
             default: 3
+    e10s:
+        by-test-platform:
+            windows7-32/debug: both
+            default: true
     loopback-video: true
     max-run-time:
         by-test-platform:
             windows.*: 5400
             android.*: 7200
             default: 3600
     instance-size:
         by-test-platform:
@@ -1063,16 +1086,20 @@ reftest:
         by-test-platform:
             android-4.3-arm7-api-15/debug: 48
             android.*: 16
             macosx64/opt: 1
             macosx64/debug: 2
             windows8-64.*/opt: 1
             windows8-64.*/debug: 2
             default: 8
+    e10s:
+        by-test-platform:
+            windows7-32/debug: both
+            default: true
     max-run-time:
         by-test-platform:
             android.*: 10800
             default: 3600
     mozharness:
         by-test-platform:
             android.*:
                 script: android_emulator_unittest.py
@@ -1164,16 +1191,21 @@ reftest-no-accel:
             windows8-64.*: buildbot-bridge/buildbot-bridge
             default: null
     chunks:
         by-test-platform:
             macosx.*: 1
             windows8-64.*/debug: 2
             windows8-64.*/opt: 1
             default: 8
+    e10s:
+        by-test-platform:
+            linux64-jsdcov/opt: false
+            windows7-32/debug: both
+            default: true
     mozharness:
         script: desktop_unittest.py
         no-read-buildbot-config: true
         chunked:
             by-test-platform:
                 windows8-64.*/opt: true
                 macosx.*: false
                 default: true
@@ -1189,17 +1221,16 @@ reftest-no-accel:
         extra-options:
             - --reftest-suite=reftest-no-accel
 
 reftest-stylo:
     description: "Reftest run for Stylo"
     suite: reftest/reftest-stylo
     treeherder-symbol: tc-R(Rs)
     virtualization: virtual-with-gpu
-    docker-image: {"in-tree": "desktop1604-test"}
     chunks: 16
     run-on-projects:
         by-test-platform:
             windows10.*: []
             default: ['autoland', 'mozilla-central', 'try']
     mozharness:
         script: desktop_unittest.py
         no-read-buildbot-config: true
@@ -2045,16 +2076,20 @@ web-platform-tests:
         macosx64/debug: 10
         default: 12
     max-run-time: 7200
     instance-size: xlarge
     run-on-projects:
         by-test-platform:
             .*-stylo.*: ['autoland', 'mozilla-central', 'try']
             default: built-projects
+    e10s:
+        by-test-platform:
+            windows7-32/debug: both
+            default: true
     mozharness:
         script: web_platform_tests.py
         no-read-buildbot-config: true
         chunked: true
         config:
             by-test-platform:
                 windows.*:
                     - web_platform_tests/prod_config_windows_taskcluster.py
@@ -2073,20 +2108,19 @@ web-platform-tests-headless:
     chunks:
       by-test-platform:
         macosx64/opt: 5
         macosx64/debug: 10
         default: 12
     e10s:
         by-test-platform:
             macosx.*: true
-            default: both
+            default: true
     max-run-time: 7200
     instance-size: xlarge
-    docker-image: {"in-tree": "desktop1604-test"}
     run-on-projects: [] # disabled pending releng approval
     mozharness:
         script: web_platform_tests.py
         no-read-buildbot-config: true
         chunked: true
         config:
             by-test-platform:
                 windows.*:
@@ -2117,16 +2151,20 @@ web-platform-tests-reftests:
       by-test-platform:
         macosx.*: 1
         windows.*: 1
         default: 6
     run-on-projects:
         by-test-platform:
             .*-stylo.*: ['autoland', 'mozilla-central', 'try']
             default: built-projects
+    e10s:
+        by-test-platform:
+            windows7-32/debug: both
+            default: true
     mozharness:
         script: web_platform_tests.py
         no-read-buildbot-config: true
         config:
             by-test-platform:
                 windows.*:
                     - web_platform_tests/prod_config_windows_taskcluster.py
                 macosx.*:
@@ -2145,19 +2183,18 @@ web-platform-tests-reftests-headless:
     instance-size: xlarge
     chunks:
       by-test-platform:
         macosx.*: 1
         windows.*: 1
         default: 6
     e10s:
         by-test-platform:
-            macosx.*: true
-            default: both
-    docker-image: {"in-tree": "desktop1604-test"}
+            windows7-32/debug: both
+            default: true
     run-on-projects: [] # disabled pending releng approval
     mozharness:
         script: web_platform_tests.py
         no-read-buildbot-config: true
         config:
             by-test-platform:
                 windows.*:
                     - web_platform_tests/prod_config_windows_taskcluster.py
@@ -2198,17 +2235,16 @@ web-platform-tests-wdspec:
             - --test-type=wdspec
 
 web-platform-tests-wdspec-headless:
     description: "Web platform webdriver-spec headless run"
     suite: web-platform-tests-wdspec
     treeherder-symbol: tc-W(WdH)
     max-run-time: 5400
     instance-size: xlarge
-    docker-image: {"in-tree": "desktop1604-test"}
     run-on-projects: [] # disabled pending releng approval
     mozharness:
         script: web_platform_tests.py
         no-read-buildbot-config: true
         config:
             by-test-platform:
                 windows.*:
                     - web_platform_tests/prod_config_windows_taskcluster.py