Both are showing a shutdownhang, but not the cause.

Start Firefox in Safe Mode {web Link} by holding down the <Shift>
(Mac=Options) key, and then starting Firefox. Is the problem still there?

While still in Safe Mode,

on each computer (use some kind of label)

Type about:support in the address bar and press Enter. Under the main banner, press the button; Copy Text To Clipboard.. Then in the reply box at the bottom of this page, do a right click in the box and select Paste. This will show us your system details. No Personal Information Is Collected.

Same problem on the first computer whilst in Firefox Safe Mode:

Application Basics

Name: Firefox Version: 43.0.4 Build ID: 20160105164030 Update Channel: release User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:43.0) Gecko/20100101 Firefox/43.0 Multiprocess Windows: 0/1 (default: false) Safe Mode: true

Crash Reports for the Last 3 Days

Report ID: bp-c888d3f4-c2ea-48f0-8bf0-d51cb2160125 Submitted: 8 minutes ago

Report ID: bp-d2d8f132-6824-45b6-a66f-3f7132160125 Submitted: 5 hours ago

Report ID: bp-1f47d49a-3a24-4804-9e74-3b6942160125 Submitted: 5 hours ago

All Crash Reports

Extensions

Graphics

Adapter Description: Intel(R) HD Graphics 3000 Adapter Drivers: igdumd64 igd10umd64 igd10umd64 igdumd32 igd10umd32 igd10umd32 Adapter RAM: Unknown Asynchronous Pan/Zoom: none Device ID: 0x0116 DirectWrite Enabled: false (6.2.9200.17568) Driver Date: 5-26-2015 Driver Version: 9.17.10.4229 GPU #2 Active: false GPU Accelerated Windows: 0/1 Basic (OMTC) Subsys ID: 05781025 Supports Hardware H264 Decoding: No; Hardware video decoding disabled or blacklisted Vendor ID: 0x8086 windowLayerManagerRemote: true AzureCanvasBackend: skia AzureContentBackend: cairo AzureFallbackCanvasBackend: cairo AzureSkiaAccelerated: 0

Important Modified Preferences

browser.cache.disk.capacity: 358400 browser.cache.disk.filesystem_reported: 1 browser.cache.disk.smart_size.first_run: false browser.cache.disk.smart_size.use_old_max: false browser.cache.frecency_experiment: 2 browser.download.importedFromSqlite: true browser.places.smartBookmarksVersion: 7 browser.sessionstore.upgradeBackup.latestBuildID: 20160105164030 browser.startup.homepage_override.buildID: 20160105164030 browser.startup.homepage_override.mstone: 43.0.4 dom.apps.reset-permissions: true dom.mozApps.used: true extensions.lastAppVersion: 43.0.4 gfx.crash-guard.d3d11layers.appVersion: 43.0.4 gfx.crash-guard.d3d11layers.deviceID: 0x0116 gfx.crash-guard.d3d11layers.driverVersion: 9.17.10.4229 gfx.crash-guard.d3d11layers.feature-d2d: true gfx.crash-guard.d3d11layers.feature-d3d11: true gfx.crash-guard.glcontext.gfx.driver-init.direct3d11-angle: true gfx.crash-guard.glcontext.gfx.driver-init.webgl-angle: true gfx.crash-guard.glcontext.gfx.driver-init.webgl-angle-force-d3d11: false gfx.crash-guard.glcontext.gfx.driver-init.webgl-angle-force-warp: false gfx.crash-guard.glcontext.gfx.driver-init.webgl-angle-try-d3d11: true gfx.crash-guard.status.d3d11layers: 2 gfx.crash-guard.status.d3d9video: 2 gfx.crash-guard.status.glcontext: 1 gfx.direct3d.last_used_feature_level_idx: 0 media.gmp-eme-adobe.abi: x86-msvc media.gmp-eme-adobe.lastUpdate: 1453747800 media.gmp-eme-adobe.version: 15 media.gmp-gmpopenh264.abi: x86-msvc media.gmp-gmpopenh264.lastUpdate: 1453747805 media.gmp-gmpopenh264.version: 1.5.3 media.gmp-manager.buildID: 20160105164030 media.gmp-manager.lastCheck: 1453747795 media.hardware-video-decoding.failed: true network.cookie.prefsMigrated: true network.predictor.cleaned-up: true places.history.expiration.transient_current_max_pages: 103399 plugin.disable_full_page_plugin_for_types: application/pdf privacy.sanitize.migrateFx3Prefs: true storage.vacuum.last.index: 0

Important Locked Preferences

JavaScript

Incremental GC: true

Accessibility

Activated: false Prevent Accessibility: 0

Library Versions

NSPR Expected minimum version: 4.10.10 Version in use: 4.10.10

NSS Expected minimum version: 3.20.2 Basic ECC Version in use: 3.20.2 Basic ECC

NSSSMIME Expected minimum version: 3.20.2 Basic ECC Version in use: 3.20.2 Basic ECC

NSSSSL Expected minimum version: 3.20.2 Basic ECC Version in use: 3.20.2 Basic ECC

NSSUTIL Expected minimum version: 3.20.2 Version in use: 3.20.2

Experimental Features

And Firefox Safe mode makes no difference on the other one either.

Results: Application Basics

Name: Firefox Version: 43.0.4 Build ID: 20160105164030 Update Channel: release User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:43.0) Gecko/20100101 Firefox/43.0 Multiprocess Windows: 0/1 (default: false) Safe Mode: true

Crash Reports for the Last 3 Days

Report ID: bp-c888d3f4-c2ea-48f0-8bf0-d51cb2160125 Submitted: 8 minutes ago

Report ID: bp-d2d8f132-6824-45b6-a66f-3f7132160125 Submitted: 5 hours ago

Report ID: bp-1f47d49a-3a24-4804-9e74-3b6942160125 Submitted: 5 hours ago

All Crash Reports

Extensions

Graphics

Adapter Description: Intel(R) HD Graphics 3000 Adapter Drivers: igdumd64 igd10umd64 igd10umd64 igdumd32 igd10umd32 igd10umd32 Adapter RAM: Unknown Asynchronous Pan/Zoom: none Device ID: 0x0116 DirectWrite Enabled: false (6.2.9200.17568) Driver Date: 5-26-2015 Driver Version: 9.17.10.4229 GPU #2 Active: false GPU Accelerated Windows: 0/1 Basic (OMTC) Subsys ID: 05781025 Supports Hardware H264 Decoding: No; Hardware video decoding disabled or blacklisted Vendor ID: 0x8086 windowLayerManagerRemote: true AzureCanvasBackend: skia AzureContentBackend: cairo AzureFallbackCanvasBackend: cairo AzureSkiaAccelerated: 0

Important Modified Preferences

browser.cache.disk.capacity: 358400 browser.cache.disk.filesystem_reported: 1 browser.cache.disk.smart_size.first_run: false browser.cache.disk.smart_size.use_old_max: false browser.cache.frecency_experiment: 2 browser.download.importedFromSqlite: true browser.places.smartBookmarksVersion: 7 browser.sessionstore.upgradeBackup.latestBuildID: 20160105164030 browser.startup.homepage_override.buildID: 20160105164030 browser.startup.homepage_override.mstone: 43.0.4 dom.apps.reset-permissions: true dom.mozApps.used: true extensions.lastAppVersion: 43.0.4 gfx.crash-guard.d3d11layers.appVersion: 43.0.4 gfx.crash-guard.d3d11layers.deviceID: 0x0116 gfx.crash-guard.d3d11layers.driverVersion: 9.17.10.4229 gfx.crash-guard.d3d11layers.feature-d2d: true gfx.crash-guard.d3d11layers.feature-d3d11: true gfx.crash-guard.glcontext.gfx.driver-init.direct3d11-angle: true gfx.crash-guard.glcontext.gfx.driver-init.webgl-angle: true gfx.crash-guard.glcontext.gfx.driver-init.webgl-angle-force-d3d11: false gfx.crash-guard.glcontext.gfx.driver-init.webgl-angle-force-warp: false gfx.crash-guard.glcontext.gfx.driver-init.webgl-angle-try-d3d11: true gfx.crash-guard.status.d3d11layers: 2 gfx.crash-guard.status.d3d9video: 2 gfx.crash-guard.status.glcontext: 1 gfx.direct3d.last_used_feature_level_idx: 0 media.gmp-eme-adobe.abi: x86-msvc media.gmp-eme-adobe.lastUpdate: 1453747800 media.gmp-eme-adobe.version: 15 media.gmp-gmpopenh264.abi: x86-msvc media.gmp-gmpopenh264.lastUpdate: 1453747805 media.gmp-gmpopenh264.version: 1.5.3 media.gmp-manager.buildID: 20160105164030 media.gmp-manager.lastCheck: 1453747795 media.hardware-video-decoding.failed: true network.cookie.prefsMigrated: true network.predictor.cleaned-up: true places.history.expiration.transient_current_max_pages: 103399 plugin.disable_full_page_plugin_for_types: application/pdf privacy.sanitize.migrateFx3Prefs: true storage.vacuum.last.index: 0

Important Locked Preferences

JavaScript

Incremental GC: true

Accessibility

Activated: false Prevent Accessibility: 0

Library Versions

NSPR Expected minimum version: 4.10.10 Version in use: 4.10.10

NSS Expected minimum version: 3.20.2 Basic ECC Version in use: 3.20.2 Basic ECC

NSSSMIME Expected minimum version: 3.20.2 Basic ECC Version in use: 3.20.2 Basic ECC

NSSSSL Expected minimum version: 3.20.2 Basic ECC Version in use: 3.20.2 Basic ECC

NSSUTIL Expected minimum version: 3.20.2 Version in use: 3.20.2

Experimental Features

Thanks for the help!

Start your Computer in safe mode with networking. Then start Firefox. Try Safe web sites. Is the problem still there?

Starting The Computer In Safe Mode;
Free Online Encyclopedia

Strongly recommend that you remove your Package Installer & Install Conduit plug-in which is malware. Google "conduit software malware" to get the general idea and removal advice. Do you use Conduit? Do you know what it is?

@FredMcD - Windows Safe Mode has the same problem. I'm going to attempt in place upgrades of Windows.

@alan_r - I've run scans and removed Conduit. I've also run JRT and ADWCleaner. Where do you see that I still have it installed?

It may be in the troubleshooting information that was added to the thread. Was it removed after posting the first post? EDIT - also the bugs on the crash report currently look at Network with gfid authentication, do you have a card reader?

Package Installer & Install Conduit is shown in the plug-ins in the Additional System Details(top right of the page) with your first post. Perhaps you had already removed some other aspects of the Conduit Search family.

@alan_r - Oh, right. I'm posting on another computer (which I now see has Conduit on it). Grrr..

Doing an inplace upgrade has fixed both computers, but the problem is now occuring on three more (all of these are running Firefox 44.0. Is there a problem with the latest 43 and 44 that makes this problem more likely, or am I just doing something wrong?

Repair install (or inplace upgrade) has fixed every computer so far, but the problem is getting more prevalent (I've now seen it on six computers) so I think there must be some issues with FF43/44.

It looks like disabling DNS and DHCP client services helps. Hopefully that's a clue.