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.

You have a masking-agent extension installed that changes the user agent:

• User Agent: Mozilla/5.0 (masking-agent; rv:33.0) Gecko/20100101

I see that at least six questions you asked before have this modified user agent.

• [/questions/996976]
  useragent: Mozilla/5.0 (masking-agent; rv:25.0) Gecko/20100101 Firefox/25.0
• [/questions/978575]
  useragent: Mozilla/5.0 (masking-agent; rv:25.0) Gecko/20100101 Firefox/25.0

Did this never caused a problem before? You will have to make sure that you have the correct user agent.

Start Firefox in Safe Mode to check if one of the extensions (Firefox menu button/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem.

• Switch to the DEFAULT theme: Firefox menu button/Tools > Add-ons > Appearance
• Do NOT click the Reset button on the Safe Mode start window

• https://support.mozilla.org/kb/Safe+Mode
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

See also:

• https://support.mozilla.org/kb/websites-say-firefox-outdated-or-incompatible

FredMcD said

This will show us your system details. No Personal Information Is Collected.

Name: Firefox Version: 42.0 Build ID: 20151029151421 Update Channel: release User Agent: Mozilla/5.0 (masking-agent; rv:35.0) Gecko/20100101 Firefox/35.0 Multiprocess Windows: 0/1 (default: false) Safe Mode: false

Crash Reports for the Last 3 Days

All Crash Reports

Extensions

Name: AdDetector Version: 0.19 Enabled: true ID: 19b15b40-23f9-11e4-8c21-0800200c9a66@jetpack

Name: All the Tools Version: 1.1-signed Enabled: true ID: palettepeek@ns.petersimonyi.ca

Name: AutoCopy 2 Version: 1.2.9.1-signed Enabled: true ID: autocopy2@teo.pl

Name: BrowserProtect Version: 1.1.3.1-signed Enabled: true ID: browserprotect@browserprotect.com

Name: Cleanest Addon Manager Version: 7.0.1-signed Enabled: true ID: cam@sdrocking.com

Name: ColorfulTabs Version: 29.3 Enabled: true ID: {0545b830-f0aa-4d7e-8820-50a4629a56fe}

Name: CoolPreviews Version: 4.6 Enabled: true ID: {CE6E6E3B-84DD-4cac-9F63-8D2AE4F30A4B}

Name: Disable clipboard manipulations Version: 1.0.1.1-signed Enabled: true ID: nocopypaste@adblockplus.org

Name: eCleaner Version: 1.4.1-signed Enabled: true ID: {c72c0c73-4eb0-4fb3-af0f-074e97326cfd}

Name: Extensor Version: 3.5 Enabled: true ID: extensor@pjs.nl

Name: Fasterfox Version: 3.9.85.1-signed Enabled: true ID: {c36177c0-224a-11da-8cd6-0800200c9a91}

Name: Flagfox Version: 5.1.5 Enabled: true ID: {1018e4d6-728f-4b20-ad56-37578a4de76b}

Name: Forecastfox (fix version) Version: 2.3.3 Enabled: true ID: forecastfox@s3_fix_version

Name: Ghostery Version: 5.4.9 Enabled: true ID: firefox@ghostery.com

Name: Google search link fix Version: 1.5.2 Enabled: true ID: jid0-XWJxt5VvCXkKzQK99PhZqAn7Xbg@jetpack

Name: HTTPS-Everywhere Version: 5.1.1 Enabled: true ID: https-everywhere-eff@eff.org

Name: IDM integration Version: 6.25.3 Enabled: true ID: mozilla_cc2@internetdownloadmanager.com

Name: IE View Version: 1.5.6.1-signed Enabled: true ID: {6e84150a-d526-41f1-a480-a67d3fed910d}

Name: InstantFox Version: 3.0.2 Enabled: true ID: searchy@searchy

Name: LastPass Version: 3.2.21 Enabled: true ID: support@lastpass.com

Name: Location Bar Enhancer Version: 5.2.1-signed Enabled: true ID: UIEnhancer@girishsharma

Name: Masking Agent Version: 1.4.0.1-signed Enabled: true ID: maskingagent@basa.nl

Name: Menu Wizard Version: 3.04 Enabled: true ID: s3menu@wizard

Name: Mozilla Archive Format Version: 3.1.1 Enabled: true ID: {7f57cf46-4467-4c2d-adfa-0cba7c507e54}

Name: Privacy Badger Version: 1.0.3 Enabled: true ID: jid1-MnnxcxisBPnSXQ@jetpack

Name: Privacy Settings Version: 0.1.7.1 Enabled: true ID: jid1-CKHySAadH4nL6Q@jetpack

Name: Private Browsing Personas Version: 0.1.1-signed Enabled: true ID: pbm-personas@dactyl.googlecode.com

Name: QuickFox Notes Version: 2.8.5.1-signed Enabled: true ID: amin.eft_bmnotes@gmail.com

Name: RefControl Version: 0.8.17.1-signed Enabled: true ID: {455D905A-D37C-4643-A9E2-F6FEFAA0424A}

Name: Restart application Version: 1.2.1.1-signed Enabled: true ID: {c0af4d2f-2ce4-9471-49e2-1e5ca8a57dd2}

Name: SearchPreview Version: 8.6 Enabled: true ID: {EF522540-89F5-46b9-B6FE-1829E2B572C6}

Name: Self-Destructing Cookies Version: 0.4.8 Enabled: true ID: jid0-9XfBwUWnvPx4wWsfBWMCm4Jj69E@jetpack

Name: Skip Cert Error Version: 0.4.4.1-signed Enabled: true ID: skipcerterror@foudil.fr

Name: Status-4-Evar Version: 2015.11.16.23 Enabled: true ID: status4evar@caligonstudios.com

Name: Tab Mix Plus Version: 0.4.1.9 Enabled: true ID: {dc572301-7619-498c-a57d-39143191b318}

Name: Tab Numbers Version: 41.0 Enabled: true ID: {074fcdbc-b3f9-43d4-afa3-f7735f1d883d}

Name: uBlock Origin Version: 1.3.2 Enabled: true ID: uBlock0@raymondhill.net

Name: Unhide Passwords Version: 1.2.7.0.1-signed Enabled: true ID: {2e17e2b2-b8d4-4a67-8d7b-fafa6cc9d1d0}

Name: UnMHT Version: 8.0.0 Enabled: true ID: {f759ca51-3a91-4dd1-ae78-9db5eee9ebf0}

Name: YouTube ALL HTML5 Version: 3.0.1 Enabled: true ID: jid1-qj0w91o64N7Eeg@jetpack

Name: IDM CC Version: 7.3.110 Enabled: false ID: mozilla_cc@internetdownloadmanager.com

Graphics

Adapter Description: Intel(R) HD Graphics 4600 Adapter Description (GPU #2): NVIDIA GeForce GTX 860M Adapter Drivers: igdumdim64 igd10iumd64 igd10iumd64 igd12umd64 igdumdim32 igd10iumd32 igd10iumd32 igd12umd32 Adapter Drivers (GPU #2): nvd3dumx,nvwgf2umx,nvwgf2umx,nvwgf2umx nvd3dum,nvwgf2um,nvwgf2um,nvwgf2um Adapter RAM: Unknown Adapter RAM (GPU #2): 2048 Asynchronous Pan/Zoom: none Device ID: 0x0416 Device ID (GPU #2): 0x1392 Direct2D Enabled: true DirectWrite Enabled: true (10.0.10240.16430) Driver Date: 7-17-2015 Driver Date (GPU #2): 7-13-2015 Driver Version: 10.18.15.4256 Driver Version (GPU #2): 10.18.13.5354 GPU #2 Active: false GPU Accelerated Windows: 1/1 Direct3D 11 (OMTC) Subsys ID: 185d1043 Subsys ID (GPU #2): 185d1043 Supports Hardware H264 Decoding: true Vendor ID: 0x8086 Vendor ID (GPU #2): 0x10de windowLayerManagerRemote: true AzureCanvasBackend: direct2d 1.1 AzureContentBackend: direct2d 1.1 AzureFallbackCanvasBackend: cairo AzureSkiaAccelerated: 0 (#0) Error: [D2D1.1] 4CreateBitmap failure Size(16,21400) Code: 0x80070057 format 0 (#1) Error: [D2D1.1] 4CreateBitmap failure Size(16,21400) Code: 0x80070057 format 0 (#2) Error: [D2D1.1] 4CreateBitmap failure Size(16,21400) Code: 0x80070057 format 0

Important Modified Preferences

accessibility.typeaheadfind.flashBar: 0 browser.cache.disk.capacity: 276480 browser.cache.disk.filesystem_reported: 1 browser.cache.disk.parent_directory: B:\ 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: 2 browser.download.importedFromSqlite: true browser.link.open_newwindow: 1 browser.places.smartBookmarksVersion: 7 browser.privatebrowsing.autostart: true browser.search.suggest.enabled: false browser.search.useDBForOrder: true browser.sessionstore.max_tabs_undo: 8 browser.sessionstore.restore_on_demand: false browser.sessionstore.resume_from_crash: false browser.startup.homepage: about:blank browser.startup.homepage_override.buildID: 20151029151421 browser.startup.homepage_override.mstone: 42.0 browser.tabs.loadInBackground: false browser.tabs.warnOnClose: false browser.tabs.warnOnOpen: false browser.urlbar.autocomplete.enabled: false browser.urlbar.suggest.bookmark: false browser.urlbar.suggest.history: false browser.urlbar.suggest.openpage: false dom.apps.reset-permissions: true dom.battery.enabled: false dom.mozApps.used: true extensions.lastAppVersion: 42.0 font.internaluseonly.changed: false general.useragent.override: Mozilla/5.0 (masking-agent; rv:35.0) Gecko/20100101 Firefox/35.0 gfx.direct3d.last_used_feature_level_idx: 0 gfx.driver-init.appVersion: 42.0 gfx.driver-init.deviceID: 0x0416 gfx.driver-init.driverVersion: 10.18.15.4256 gfx.driver-init.feature-d2d: true gfx.driver-init.feature-d3d11: true gfx.driver-init.status: 2 media.eme.enabled: false media.gmp-eme-adobe.enabled: false media.gmp-gmpopenh264.lastUpdate: 1432146316 media.gmp-gmpopenh264.version: 1.4 media.gmp-manager.buildID: 20151029151421 media.gmp-manager.lastCheck: 1447948210 media.hardware-video-decoding.failed: false media.peerconnection.enabled: false network.auth.allow-subresource-auth: 2 network.cookie.prefsMigrated: true network.http.max-persistent-connections-per-server: 32 network.http.pipelining.max-optimistic-requests: 8 network.http.speculative-parallel-limit: 0 network.predictor.cleaned-up: true network.prefetch-next: false network.websocket.enabled: false places.database.lastMaintenance: 1447953678 places.history.expiration.transient_current_max_pages: 104858 plugin.disable_full_page_plugin_for_types: application/pdf plugin.importedState: true print.printer_pdfFactory_Pro.print_bgcolor: false print.printer_pdfFactory_Pro.print_bgimages: false print.printer_pdfFactory_Pro.print_colorspace: print.printer_pdfFactory_Pro.print_command: print.printer_pdfFactory_Pro.print_downloadfonts: false print.printer_pdfFactory_Pro.print_duplex: 1515870810 print.printer_pdfFactory_Pro.print_edge_bottom: 0 print.printer_pdfFactory_Pro.print_edge_left: 0 print.printer_pdfFactory_Pro.print_edge_right: 0 print.printer_pdfFactory_Pro.print_edge_top: 0 print.printer_pdfFactory_Pro.print_evenpages: true print.printer_pdfFactory_Pro.print_footercenter: print.printer_pdfFactory_Pro.print_footerleft: &PT print.printer_pdfFactory_Pro.print_footerright: &D print.printer_pdfFactory_Pro.print_headercenter: print.printer_pdfFactory_Pro.print_headerleft: &T print.printer_pdfFactory_Pro.print_headerright: &U print.printer_pdfFactory_Pro.print_in_color: true print.printer_pdfFactory_Pro.print_margin_bottom: 0.5 print.printer_pdfFactory_Pro.print_margin_left: 0.5 print.printer_pdfFactory_Pro.print_margin_right: 0.5 print.printer_pdfFactory_Pro.print_margin_top: 0.5 print.printer_pdfFactory_Pro.print_oddpages: true print.printer_pdfFactory_Pro.print_orientation: 0 print.printer_pdfFactory_Pro.print_page_delay: 50 print.printer_pdfFactory_Pro.print_paper_data: 1 print.printer_pdfFactory_Pro.print_paper_height: 11.00 print.printer_pdfFactory_Pro.print_paper_name: print.printer_pdfFactory_Pro.print_paper_size_type: 0 print.printer_pdfFactory_Pro.print_paper_size_unit: 0 print.printer_pdfFactory_Pro.print_paper_width: 8.50 print.printer_pdfFactory_Pro.print_plex_name: print.printer_pdfFactory_Pro.print_resolution: 1515870810

cor-el said

You have a masking-agent extension installed that changes the user agent:

• User Agent: Mozilla/5.0 (masking-agent; rv:33.0) Gecko/20100101

I'm going to remove Masking Agent just to see if that works. Thanks.