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,

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.

Hi. Thanks for your reply. When in Safe Mode, everything is fine and the problem does not exist. As requested, please see below:

Application Basics

Name: Firefox Version: 42.0 Build ID: 20151029151421 Update Channel: release User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:42.0) Gecko/20100101 Firefox/42.0 Multiprocess Windows: 0/1 (default: false) Safe Mode: true

Crash Reports for the Last 3 Days

All Crash Reports

Extensions

Graphics

Asynchronous Pan/Zoom: none Device ID: 0x0fd5 GPU Accelerated Windows: 0/1 Basic Supports Hardware H264 Decoding: false Vendor ID: 0x10de windowLayerManagerRemote: false AzureCanvasBackend: skia AzureContentBackend: quartz AzureFallbackCanvasBackend: none 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.frecency_experiment: 1 browser.download.importedFromSqlite: true browser.places.smartBookmarksVersion: 7 browser.sessionstore.upgradeBackup.latestBuildID: 20151029151421 browser.startup.homepage_override.buildID: 20151029151421 browser.startup.homepage_override.mstone: 42.0 dom.apps.reset-permissions: true dom.mozApps.used: true extensions.lastAppVersion: 42.0 media.gmp-gmpopenh264.abi: x86-gcc3-u-i386-x86_64 media.gmp-gmpopenh264.lastUpdate: 1449064573 media.gmp-gmpopenh264.version: 1.5.1 media.gmp-manager.buildID: 20151029151421 media.gmp-manager.lastCheck: 1449064572 network.cookie.prefsMigrated: true network.predictor.cleaned-up: true places.database.lastMaintenance: 1449065392 places.history.expiration.transient_current_max_pages: 104858 plugin.disable_full_page_plugin_for_types: application/pdf plugin.importedState: true plugin.state.nplastpass: 0 privacy.sanitize.migrateFx3Prefs: true storage.vacuum.last.index: 0 storage.vacuum.last.places.sqlite: 1449065390

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: 3.19.4 Basic ECC Version in use: 3.19.4 Basic ECC

NSSSMIME Expected minimum version: 3.19.4 Basic ECC Version in use: 3.19.4 Basic ECC

NSSSSL Expected minimum version: 3.19.4 Basic ECC Version in use: 3.19.4 Basic ECC

NSSUTIL Expected minimum version: 3.19.4 Version in use: 3.19.4

Experimental Features

Do you have any add-ons? I don't see any listed.

Start Firefox in Safe Mode {web link} While you are in safe mode;

Type about:preferences#advanced<Enter> in the address bar.

Under Advanced, Select General. Look for and turn off Use Hardware Acceleration.

Restart Firefox. Are there any problems?

Hi. That solved it!

Many thanks for your help. Much appreciated

Hello,

I am glad to hear that your problem has been resolved. If you haven't already, please select the answer that solves the problem. This will help other users with similar problems find the solution more easily.

Thank you for contacting Mozilla Support.