Firefox comes in two or more folders on all computers. They are;

Maintenance: (Programs Folder) <Windows Only> Firefox itself: (Programs Folder) And one folder in the profile of each user on the computer.

If you remove the Firefox folder, the user folders would not be effected.

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

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.

I uninstalled and reinstalled firefox and I'm still having problems

Please provide the about:support info that Fred requested and also explain your "problems" in detail.

wait how do I do that?

FredMcD said

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.

See also:

• https://support.mozilla.org/kb/Using+the+Troubleshooting+Information+page

Application Basics

Name: Firefox Version: 40.0.3 Build ID: 20150826023504 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: Adblock Plus Version: 2.6.10 Enabled: true ID: {d10d0bf8-f5b5-c8b4-a8b2-2b9879e08c5d}

Name: Dangerous Websites Blocker Version: 4.5.1.379 Enabled: true ID: content_blocker_663BE84DBCC949E88C7600F63CA7F098@kaspersky.com

Name: Feedly Notifier Version: 2.10.8 Enabled: true ID: jid1-BOjn8b0IM7kH2w@jetpack

Name: Safe Money Version: 4.5.1.379 Enabled: true ID: online_banking_08806E753BE44495B44E90AA2513BDC5@kaspersky.com

Name: Virtual Keyboard Version: 4.5.1.379 Enabled: true ID: virtual_keyboard_07402848C2F6470194F131B0F3DE025E@kaspersky.com

Name: Adobe Acrobat - Create PDF Version: 1.2 Enabled: false ID: web2pdfextension@web2pdf.adobedotcom

Graphics

Adapter Description: AMD Radeon R9 200 Series Adapter Drivers: aticfx64 aticfx64 aticfx64 aticfx32 aticfx32 aticfx32 atiumd64 atidxx64 atidxx64 atiumdag atidxx32 atidxx32 atiumdva atiumd6a atitmm64 Adapter RAM: 4095 Asynchronous Pan/Zoom: none Device ID: 0x67b0 DirectWrite Enabled: false (6.2.9200.17461) Driver Date: 7-28-2015 Driver Version: 15.200.1062.1003 GPU #2 Active: false GPU Accelerated Windows: 0/1 Basic (OMTC) Subsys ID: 0b001002 Supports Hardware H264 Decoding: false Vendor ID: 0x1002 WebGL Renderer: Google Inc. -- ANGLE (AMD Radeon R9 200 Series Direct3D11 vs_5_0 ps_5_0) windowLayerManagerRemote: true AzureCanvasBackend: skia AzureContentBackend: cairo AzureFallbackCanvasBackend: cairo 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.disk.smart_size.use_old_max: false browser.cache.frecency_experiment: 1 browser.download.importedFromSqlite: true browser.places.smartBookmarksVersion: 7 browser.sessionstore.upgradeBackup.latestBuildID: 20150826023504 browser.startup.homepage_override.buildID: 20150826023504 browser.startup.homepage_override.mstone: 40.0.3 dom.allow_scripts_to_close_windows: true dom.apps.reset-permissions: true dom.mozApps.used: true extensions.lastAppVersion: 40.0.3 gfx.direct2d.disabled: true gfx.direct3d.last_used_feature_level_idx: 0 layers.acceleration.disabled: true media.gmp-eme-adobe.lastUpdate: 1442525796 media.gmp-eme-adobe.version: 13 media.gmp-gmpopenh264.lastUpdate: 1442289793 media.gmp-gmpopenh264.version: 1.4 media.gmp-manager.buildID: 20150826023504 media.gmp-manager.lastCheck: 1442634848 network.auth.allow-subresource-auth: 2 network.cookie.prefsMigrated: true network.predictor.cleaned-up: true places.database.lastMaintenance: 1442365867 places.history.expiration.transient_current_max_pages: 104858 plugin.disable_full_page_plugin_for_types: application/pdf plugin.importedState: true plugin.state.npcontentblocker: 2 plugin.state.nponlinebanking: 2 plugin.state.npvkplugin: 2 privacy.sanitize.migrateFx3Prefs: true storage.vacuum.last.index: 1 storage.vacuum.last.places.sqlite: 1442365867

user.js Preferences

Your profile folder contains a user.js file, which includes preferences that were not created by Firefox.

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

Your profile folder contains a user.js file, which includes preferences that were not created by Firefox.

Now please describe your problem.

You can check for problems with the places.sqlite ??db file (bookmarks, history) in the Firefox profile folder.

• Places Maintenance: https://addons.mozilla.org/firefox/addon/places-maintenance/

• http://kb.mozillazine.org/Bookmarks_history_and_toolbar_buttons_not_working_-_Firefox
• https://support.mozilla.org/kb/Bookmarks+not+saved#w_fix-the-bookmarks-file

If the PM extension doesn't help then remove all places.sqlite file(s) in the Firefox profile folder to make Firefox rebuild the places.sqlite database file from the most recent JSON backup (bookmarks-YYYY-MM-DD_<item-count>_<hash>.jsonlz4) in the bookmarkbackups folder.

You can use this button to go to the current Firefox profile folder:

• Help > Troubleshooting Information > Profile Directory: Show Folder (Linux: Open Directory; Mac: Show in Finder)
• http://kb.mozillazine.org/Profile_folder_-_Firefox

I tried the add-on and it's still doing it and the weird part it's only on youtube the lag is happening.