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...

Hello Philipp,

Thank you for your reply. Please remove my full name in the post of the forum, I was not aware of that. Here is the info you ask for:

Give Firefox a tune up Try Safe Mode Troubleshooting Information This page contains technical information that might be useful when you're trying to solve a problem. If you are looking for answers to common questions about Firefox, check out our support web site. Application Basics Name Firefox Version 48.0.2 Build ID 20160823121617 Update History Update Channel release User Agent Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:48.0) Gecko/20100101 Firefox/48.0 OS Windows_NT 10.0 x86-64 Profile Folder Enabled Plugins about:plugins Build Configuration about:buildconfig Memory Use about:memory Registered Service Workers about:serviceworkers Multiprocess Windows 0/2 (Disabled) Safe Mode false Profiles about:profiles Crash Reports for the Last 3 Days Report ID Submitted

All Crash Reports Extensions Name Version Enabled ID Adblock Plus 2.7.3 true {d10d0bf8-f5b5-c8b4-a8b2-2b9879e08c5d} Firefox Hello 1.4.4 true loop@mozilla.org McAfee WebAdvisor 5.0.226.0 true {4ED1F68A-5463-4931-9384-8FFF5ED91D92} MEGA 3.4.48 true firefox@mega.co.nz Multi-process staged rollout 1.1 true e10srollout@mozilla.org Pocket 1.0.4 true firefox@getpocket.com Search and New Tab by Yahoo 1.1.0 true jid1-16aeif9OQIRKxA@jetpack BitComet Video Downloader 1.37 false {B042753D-F57E-4e8e-A01B-7379A6D4CEFB} McAfee SafeKey 2.2.3 false {072844D3-7DEE-45F6-A406-E87F76302E4B} Graphics Features Compositing Direct3D 11 Asynchronous Pan/Zoom none WebGL Renderer Google Inc. -- ANGLE (NVIDIA GeForce GTX 645 Direct3D11 vs_5_0 ps_5_0) Hardware H264 Decoding Yes; Using D3D11 API Direct2D true DirectWrite true (10.0.10586.494) GPU #1 Active Yes Description NVIDIA GeForce GTX 645 Vendor ID 0x10de Device ID 0x11c4 Driver Version 10.18.13.5382 Driver Date 8-7-2015 Drivers nvd3dumx,nvwgf2umx,nvwgf2umx,nvwgf2umx nvd3dum,nvwgf2um,nvwgf2um,nvwgf2um Subsys ID 00000000 RAM 2048 Diagnostics AzureCanvasAccelerated 0 AzureCanvasBackend direct2d 1.1 AzureContentBackend direct2d 1.1 AzureFallbackCanvasBackend cairo Important Modified Preferences Name Value accessibility.typeaheadfind.casesensitive 1 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_cached_value 358400 browser.cache.disk.smart_size.first_run false browser.cache.disk.smart_size.use_old_max false browser.cache.frecency_experiment 4 browser.download.importedFromSqlite true browser.download.manager.alertOnEXEOpen true browser.download.useDownloadDir false browser.link.open_newwindow 2 browser.places.smartBookmarksVersion 8 browser.search.useDBForOrder true browser.sessionstore.upgradeBackup.latestBuildID 20160823121617 browser.startup.homepage https://www.google.com/advanced_search browser.startup.homepage_override.buildID 20160823121617 browser.startup.homepage_override.mstone 48.0.2 browser.tabs.loadInBackground false browser.urlbar.suggest.bookmark false browser.urlbar.suggest.openpage false browser.urlbar.userMadeSearchSuggestionsChoice true dom.apps.reset-permissions true dom.mozApps.used true extensions.lastAppVersion 48.0.2 font.internaluseonly.changed false gfx.crash-guard.d3d11layers.appVersion 48.0.2 gfx.crash-guard.d3d11layers.deviceID 0x11c4 gfx.crash-guard.d3d11layers.driverVersion 10.18.13.5382 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. 2 gfx.crash-guard.status.d3d11layers 2 gfx.crash-guard.status.d3d9video 2 gfx.crash-guard.status.glcontext 2 gfx.direct3d.last_used_feature_level_idx 0 media.benchmark.vp9.fps 180 media.benchmark.vp9.versioncheck 1 media.gmp-manager.buildID 20160823121617 media.gmp-manager.lastCheck 1472454440 media.gmp.storage.version.observed 1 media.hardware-video-decoding.failed false media.webrtc.debug.aec_log_dir C:\Users\Han\AppData\Local\Temp/ media.webrtc.debug.log_file C:\Users\Han\AppData\Local\Temp/WebRTC.log network.cookie.prefsMigrated true network.predictor.cleaned-up true places.database.lastMaintenance 1472413262 places.history.expiration.transient_current_max_pages 104858 plugin.disable_full_page_plugin_for_types application/pdf plugin.importedState true plugin.state.npmcsnffpl 1 plugin.state.nppl 2 plugin.state.nprndlhtml5videoshim 1 plugin.state.nprpplugin 2 print.printer_HP_ePrint.print_bgcolor false print.printer_HP_ePrint.print_bgimages false print.printer_HP_ePrint.print_colorspace print.printer_HP_ePrint.print_command print.printer_HP_ePrint.print_downloadfonts false print.printer_HP_ePrint.print_duplex 1515870810 print.printer_HP_ePrint.print_edge_bottom 0 print.printer_HP_ePrint.print_edge_left 0 print.printer_HP_ePrint.print_edge_right 0 print.printer_HP_ePrint.print_edge_top 0 print.printer_HP_ePrint.print_evenpages true print.printer_HP_ePrint.print_footercenter print.printer_HP_ePrint.print_footerleft &PT print.printer_HP_ePrint.print_footerright &D print.printer_HP_ePrint.print_headercenter print.printer_HP_ePrint.print_headerleft &T print.printer_HP_ePrint.print_headerright &U print.printer_HP_ePrint.print_in_color true print.printer_HP_ePrint.print_margin_bottom 0.5 print.printer_HP_ePrint.print_margin_left 0.5 print.printer_HP_ePrint.print_margin_right 0.5 print.printer_HP_ePrint.print_margin_top 0.5 print.printer_HP_ePrint.print_oddpages true print.printer_HP_ePrint.print_orientation 0 print.printer_HP_ePrint.print_page_delay 50 print.printer_HP_ePrint.print_paper_data 1 print.printer_HP_ePrint.print_paper_height 11.00 print.printer_HP_ePrint.print_paper_name print.printer_HP_ePrint.print_paper_size_type 0 print.printer_HP_ePrint.print_paper_size_unit 0 print.printer_HP_ePrint.print_paper_width 8.50 print.printer_HP_ePrint.print_plex_name print.printer_HP_ePrint.print_resolution 1515870810 print.printer_HP_ePrint.print_resolution_name print.printer_HP_ePrint.print_reversed false print.printer_HP_ePrint.print_scaling 1.00 print.printer_HP_ePrint.print_shrink_to_fit true print.printer_HP_ePrint.print_to_file false print.printer_HP_ePrint.print_unwriteable_margin_bottom 0 print.printer_HP_ePrint.print_unwriteable_margin_left 0 print.printer_HP_ePrint.print_unwriteable_margin_right 0 print.printer_HP_ePrint.print_unwriteable_margin_top 0 privacy.sanitize.migrateFx3Prefs true privacy.sanitize.timeSpan 0 security.cert_pinning.enforcement_level 0 services.sync.declinedEngines storage.vacuum.last.index 1 storage.vacuum.last.places.sqlite 1471850976 ui.osk.debug.keyboardDisplayReason IKPOS: Touch screen not found. Important Locked Preferences Name Value JavaScript Incremental GC true Accessibility Activated false Prevent Accessibility 0 Library Versions Expected minimum version Version in use NSPR 4.12 4.12 NSS 3.24 Basic ECC 3.24 Basic ECC NSSSMIME 3.24 Basic ECC 3.24 Basic ECC NSSSSL 3.24 Basic ECC 3.24 Basic ECC NSSUTIL 3.24 3.24 Experimental Features Name ID Description Active End Date Homepage Branch

thanks, can you try to replicate this behaviour when you launch firefox in safe mode once? if not, maybe an addon is interfering here...

Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems

Thank you for your suggestion. Disabling all add-ons solves the problem indeed.