hello, could you go to the firefox menu ≡ > help ? > troubleshooting information, copy the contents of that page and paste them here into a reply on the forum? this might give us a clue what is going on...

Application Basics

Name: Firefox Version: 49.0.1 Build ID: 20160922113459 Update Channel: release User Agent: OS: Linux 3.16.7-42-desktop Multiprocess Windows: 1/1 (Enabled by default) Safe Mode: false

Crash Reports for the Last 3 Days

All Crash Reports

Extensions

Name: Multi-process staged rollout Version: 1.2 Enabled: true ID: e10srollout@mozilla.org

Name: Pocket Version: 1.0.4 Enabled: true ID: firefox@getpocket.com

Name: Web Compat Version: 1.0 Enabled: true ID: webcompat@mozilla.org

Name: User-Agent Switcher Version: 0.1.8 Enabled: false ID: jid1-kyxEAcWua7BEKq@jetpack

Graphics

Features Compositing: Basic Asynchronous Pan/Zoom: wheel input enabled WebGL Renderer: X.Org R300 Project -- Gallium 0.4 on ATI RC410 Hardware H264 Decoding: No; Failed to create H264 decoder GPU #1 Active: Yes Description: X.Org R300 Project -- Gallium 0.4 on ATI RC410 Vendor ID: X.Org R300 Project Device ID: Gallium 0.4 on ATI RC410 Driver Version: 2.1 Mesa 10.3.7

Diagnostics AzureCanvasAccelerated: 0 AzureCanvasBackend: skia AzureContentBackend: cairo AzureFallbackCanvasBackend: none CairoUseXRender: 0 Decision Log HW_COMPOSITING: blocked by default: Acceleration blocked by platform

Important Modified Preferences

accessibility.browsewithcaret: true accessibility.typeaheadfind: true accessibility.typeaheadfind.flashBar: 0 browser.cache.disk.capacity: 358400 browser.cache.disk.filesystem_reported: 1 browser.cache.disk.hashstats_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.download.useDownloadDir: false browser.places.smartBookmarksVersion: 8 browser.sessionstore.upgradeBackup.latestBuildID: 20160922113459 browser.startup.homepage: file:///home/sergio/VillaDoMar.HTML browser.startup.homepage_override.buildID: 20160922113459 browser.startup.homepage_override.mstone: 49.0.1 browser.tabs.remote.autostart.2: true browser.urlbar.daysBeforeHidingSuggestionsPrompt: 0 browser.urlbar.lastSuggestionsPromptDate: 20160831 browser.urlbar.suggest.openpage: false dom.apps.lastUpdate.buildID: 20160922113459 dom.apps.lastUpdate.mstone: 49.0.1 dom.apps.reset-permissions: true dom.disable_open_during_load: false dom.mozApps.used: true extensions.lastAppVersion: 49.0.1 font.internaluseonly.changed: false font.size.variable.x-western: 20 general.useragent.override: gfx.crash-guard.glcontext.appVersion: 45.0 gfx.crash-guard.glcontext.deviceID: Gallium 0.4 on ATI RC410 gfx.crash-guard.glcontext.driverVersion: 2.1 Mesa 9.2.5 gfx.crash-guard.status.glcontext: 2 media.gmp-gmpopenh264.abi: x86-gcc3 media.gmp-gmpopenh264.lastUpdate: 1471516948 media.gmp-gmpopenh264.version: 1.6 media.gmp-manager.buildID: 20160922113459 media.gmp-manager.lastCheck: 1476356431 media.gmp.storage.version.observed: 1 media.webrtc.debug.aec_log_dir: /tmp media.webrtc.debug.log_file: /tmp/WebRTC.log media.youtube-ua.override.to: 43 network.auth.allow-subresource-auth: 2 network.cookie.prefsMigrated: true network.predictor.cleaned-up: true places.database.lastMaintenance: 1475754155 places.history.expiration.transient_current_max_pages: 46184 plugin.disable_full_page_plugin_for_types: application/pdf plugin.importedState: true plugin.state.java: 2 print.print_bgcolor: false print.print_bgimages: false print.print_colorspace: default print.print_downloadfonts: false print.print_duplex: 0 print.print_evenpages: true print.print_in_color: true print.print_margin_bottom: 0.500000012107193 print.print_margin_left: 0.500000012107193 print.print_margin_right: 0.500000012107193 print.print_margin_top: 0.500000012107193 print.print_oddpages: true print.print_orientation: 0 print.print_page_delay: 50 print.print_paper_data: 0 print.print_paper_height: 297,00 print.print_paper_name: iso_a4 print.print_paper_size_type: 1 print.print_paper_size_unit: 1 print.print_paper_width: 210,00 print.print_plex_name: default print.print_resolution_name: default print.print_scaling: 0,99 print.print_shrink_to_fit: true print.print_to_file: false print.print_unwriteable_margin_bottom: 57 print.print_unwriteable_margin_left: 13 print.print_unwriteable_margin_right: 13 print.print_unwriteable_margin_top: 6 privacy.cpd.offlineApps: true privacy.cpd.siteSettings: true privacy.sanitize.migrateClearSavedPwdsOnExit: true privacy.sanitize.migrateFx3Prefs: true privacy.trackingprotection.pbmode.enabled: false security.disable_button.openDeviceManager: false security.OCSP.enabled: 0 services.sync.declinedEngines: storage.vacuum.last.index: 1 storage.vacuum.last.places.sqlite: 1474885593

Important Locked Preferences

Places Database

JavaScript

Incremental GC: true

Accessibility

Activated: false Prevent Accessibility: 0

Library Versions

NSPR Expected minimum version: 4.12 Version in use: 4.12

NSS Expected minimum version: 3.25 Version in use: 3.25

NSSSMIME Expected minimum version: 3.25 Version in use: 3.25

NSSSSL Expected minimum version: 3.25 Version in use: 3.25

NSSUTIL Expected minimum version: 3.25 Version in use: 3.25

Experimental Features

Sandbox

Seccomp-BPF (System Call Filtering): true Seccomp Thread Synchronization: false User Namespaces: true Media Plugin Sandboxing: true

thanks, enter about:config into the firefox address bar (confirm the info message in case it shows up) & search for the preference named general.useragent.override - right-click and reset that entry to the default value.

otherwise you could also refresh your whole profile: Refresh Firefox - reset add-ons and settings

Thank You The problem is solved because your help. Mozilla suport is very good