What have you tried in the past to fix this?

Make sure everything on your system is up-to-date.

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

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

I did as you suggested and my Dell Inspiron Win 7 locked up with 4 to 6 tabs open and using the mouse to select other links. My machine stopped doing this when I updated to FF 40.0, but is back with FF 40.0.2.

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.

Application Basics

Name: Firefox Version: 40.0.2 Build ID: 20150812163655 Update Channel: release User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:40.0) Gecko/20100101 Firefox/40.0 Multiprocess Windows: 0/1 (default: false)

Crash Reports for the Last 3 Days

All Crash Reports

Extensions

Name: Addon List Dumper (restartless) Version: 0.2.1-signed Enabled: true ID: addonListDumper@jetpack

Name: Bookmark Favicon Changer Version: 2.28 Enabled: true ID: bookmarkfaviconchanger@sonthakit

Name: Dictionary Lookup Extension Version: 2.1.1-signed Enabled: true ID: {f01f4cbe-b8a8-4c37-94b3-119d8779e7e0}

Name: Download Status Bar Version: 12.3.0.1-signed Enabled: true ID: {6c28e999-e900-4635-a39d-b1ec90ba0c0f}

Name: Forecastfox (fix version) Version: 2.3.1 Enabled: true ID: forecastfox@s3_fix_version

Name: Google Translator for Firefox Version: 2.1.0.5.1 Enabled: true ID: translator@zoli.bod

Name: Restart Button Version: 0.1.5.1-signed Enabled: true ID: restartbutton@strk.jp

Name: uBlock Origin Version: 1.0.0.1 Enabled: true ID: uBlock0@raymondhill.net

Name: Uppity Version: 1.5.8.1-signed Enabled: true ID: {16cbd87c-eb99-4f5c-9825-83cf13ab7ff8}

Name: X-notifier Version: 3.5.12 Enabled: true ID: {37fa1426-b82d-11db-8314-0800200c9a66}

Name: xclear Version: 1.8.1-signed Enabled: true ID: xclear@as-computer.de

Name: HP Smart Web Printing Version: 4.60 Enabled: false ID: smartwebprinting@hp.com

Name: Norton Toolbar Version: 2015.5.2.22 Enabled: false ID: {2D3F3651-74B9-4795-BDEC-6DA2F431CB62}

Graphics

Adapter Description: Mobile Intel(R) 4 Series Express Chipset Family Adapter Drivers: igdumd64 igd10umd64 igdumdx32 igd10umd32 Adapter RAM: Unknown Asynchronous Pan/Zoom: none Device ID: 0x2a42 Direct2D Enabled: Blocked for your graphics driver version. DirectWrite Enabled: false (6.2.9200.17292) Driver Date: 11-6-2009 Driver Version: 8.15.10.1994 GPU #2 Active: false GPU Accelerated Windows: 1/1 Direct3D 11 (OMTC) Subsys ID: 02aa1028 Supports Hardware H264 Decoding: true Vendor ID: 0x8086 WebGL Renderer: Google Inc. -- ANGLE (Mobile Intel(R) 4 Series Express Chipset Family Direct3D9Ex vs_3_0 ps_3_0) windowLayerManagerRemote: true AzureCanvasBackend: skia AzureContentBackend: cairo AzureFallbackCanvasBackend: cairo AzureSkiaAccelerated: 0 (#0) Error: OpenSharedResource failed for format 65

Important Modified Preferences

accessibility.typeaheadfind.flashBar: 0 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: 1 browser.download.folderList: 0 browser.download.importedFromSqlite: true browser.places.smartBookmarksVersion: 7 browser.search.suggest.enabled: false browser.search.useDBForOrder: true browser.sessionstore.upgradeBackup.latestBuildID: 20150812163655 browser.startup.homepage: http://www.ighome.com/ browser.startup.homepage_override.buildID: 20150812163655 browser.startup.homepage_override.mstone: 40.0.2 browser.tabs.warnOnOpen: false dom.apps.reset-permissions: true dom.ipc.plugins.flash.disable-protected-mode: true dom.mozApps.used: true extensions.lastAppVersion: 40.0.2 font.name.monospace.x-western: Lucida Console font.name.sans-serif.x-western: Comic Sans MS font.name.serif.x-western: Cambria gfx.blacklist.direct2d: 3 media.gmp-eme-adobe.lastUpdate: 1437750986 media.gmp-eme-adobe.version: 12 media.gmp-gmpopenh264.enabled: true media.gmp-gmpopenh264.lastUpdate: 1437068264 media.gmp-gmpopenh264.version: 1.4 media.gmp-manager.buildID: 20150812163655 media.gmp-manager.lastCheck: 1439683487 network.cookie.prefsMigrated: true network.predictor.cleaned-up: true network.prefetch-next: false places.database.lastMaintenance: 1439218281 places.history.expiration.transient_current_max_pages: 79492 plugin.disable_full_page_plugin_for_types: application/pdf plugin.importedState: true plugin.state.npdeployjava: 0 plugin.state.npgeplugin: 0 plugin.state.npgoogleupdate: 1 plugin.state.nppdf: 2 plugin.state.npqtplugin: 1 print.printer_PrimoPDF.print_bgcolor: false print.printer_PrimoPDF.print_bgimages: false print.printer_PrimoPDF.print_colorspace: print.printer_PrimoPDF.print_command: print.printer_PrimoPDF.print_downloadfonts: false print.printer_PrimoPDF.print_duplex: 1515870810 print.printer_PrimoPDF.print_edge_bottom: 0 print.printer_PrimoPDF.print_edge_left: 0 print.printer_PrimoPDF.print_edge_right: 0 print.printer_PrimoPDF.print_edge_top: 0 print.printer_PrimoPDF.print_evenpages: true print.printer_PrimoPDF.print_footercenter: print.printer_PrimoPDF.print_footerleft: &PT print.printer_PrimoPDF.print_footerright: &D print.printer_PrimoPDF.print_headercenter: print.printer_PrimoPDF.print_headerleft: &T print.printer_PrimoPDF.print_headerright: &U print.printer_PrimoPDF.print_in_color: true print.printer_PrimoPDF.print_margin_bottom: 0.5 print.printer_PrimoPDF.print_margin_left: 0.5 print.printer_PrimoPDF.print_margin_right: 0.5 print.printer_PrimoPDF.print_margin_top: 0.5 print.printer_PrimoPDF.print_oddpages: true print.printer_PrimoPDF.print_orientation: 0 print.printer_PrimoPDF.print_page_delay: 50 print.printer_PrimoPDF.print_paper_data: 1 print.printer_PrimoPDF.print_paper_height: 11.00 print.printer_PrimoPDF.print_paper_name: print.printer_PrimoPDF.print_paper_size_type: 0 print.printer_PrimoPDF.print_paper_size_unit: 0 print.printer_PrimoPDF.print_paper_width: 8.50 print.printer_PrimoPDF.print_plex_name: print.printer_PrimoPDF.print_resolution: 1515870810 print.printer_PrimoPDF.print_resolution_name: print.printer_PrimoPDF.print_reversed: false print.printer_PrimoPDF.print_scaling: 1.00 print.printer_PrimoPDF.print_shrink_to_fit: true print.printer_PrimoPDF.print_to_file: false print.printer_PrimoPDF.print_unwriteable_margin_bottom: 0 print.printer_PrimoPDF.print_unwriteable_margin_left: 0 print.printer_PrimoPDF.print_unwriteable_margin_right: 0 print.printer_PrimoPDF.print_unwriteable_margin_top: 0 privacy.cpd.cookies: false privacy.cpd.formdata: false privacy.cpd.sessions: false privacy.donottrackheader.enabled: true privacy.sanitize.migrateFx3Prefs: true privacy.sanitize.timeSpan: 0 storage.vacuum.last.index: 0 storage.vacuum.last.places.sqlite: 1439742375

Important Locked Preferences

JavaScript

Incremental GC: true

Accessibility

Activated: true Prevent Accessibility: 0

Library Versions

NSPR Expected minimum version: 4.10.8 Version in use: 4.10.8

NSS Expected minimum version: 3.19.2 Basic ECC Version in use: 3.19.2 Basic ECC

NSSSMIME Expected minimum version: 3.19.2 Basic ECC Version in use: 3.19.2 Basic ECC

NSSSSL Expected minimum version: 3.19.2 Basic ECC Version in use: 3.19.2 Basic ECC

NSSUTIL Expected minimum version: 3.19.2 Version in use: 3.19.2

Experimental Features

• 1 Download Firefox Full Installer For All languages And Systemsv39 {web link}
• 2 Uninstall Firefox from your computer {web link}
  DO NOT remove your profiles.
• 3 After, reboot the computer. Then run the full installer.

I just completed that which you recommended. On first test, opening multiple tabs (12+) and clicking other links, it seems to be working correctly. I hope it continues. Any idea why thaqt worked as opposed to the update from FF 40.0 to FF 40.0.2 during the week?

Thank you for your help,

Major Howland

It could be a Firefox file was corrupt, and the full install replaced that file.