I do not know exactly what can be causing this. I am happy to try to help troubleshoot. Is your flash player up to date? Flash Plugin - Keep it up to date and troubleshoot problems Are you receiving an error message that says the profile is corrupt? Are you affected by the youtube band in India?

If you disable flash, does the video play in the html5 player ok?

Looking forward to your reply.

Yes I keep flash up to date. Since last posting, the new FF profile I created to export my bookmarks froze when not in Youtube. There is no error message on the screen when FF freezes. Maybe Apple doesn't want users using Firefox so it crashes it with no hints.

Did you try to clear the cache and the cookies?

You can try these steps in case of issues with web pages:

You can reload web page(s) and bypass the cache to refresh possibly outdated or corrupted files.

• Hold down the Shift key and left-click the Reload button
• Press "Ctrl + F5" or press "Ctrl + Shift + R" (Windows,Linux)
• Press "Command + Shift + R" (Mac)

Clear the cache and remove cookies only from websites that cause problems.

"Clear the Cache":

• Firefox > Preferences > Advanced > Network > Cached Web Content: "Clear Now"

"Remove Cookies" from sites causing problems:

• Firefox > Preferences > Privacy > "Use custom settings for history" > Cookies: "Show Cookies"

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

• Switch to the DEFAULT theme: Firefox/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

Start Firefox in Safe Mode {web link} While you are in safe mode; Press the Alt or F10 key to bring up the tool bar. Followed by;

Windows; Tools > Options Linux; Edit > Preferences Mac; application name > Preferences

Then Advanced > General. Look for and turn off Use Hardware Acceleration.

Poke around safe web sites. Are there any problems?

Then restart.

Yes, I clear cache and cookies and flash objects when I close Firefox. Again I created a new FF profile to export bookmarks but did some website testing but no video media. And it froze and corrupted the profile. Because of this I am currently using Safari. I also somewhere along the line troubleshooting this completely uninstalled FF and re-installed with fresh profile only for it to happen again. Maybe SSD Mac issue?

Will try.

Quote: I clear cache and cookies and flash objects when I close Firefox.

Note that Firefox disables the disk cache if you use "Clear history when Firefox closes" to clear the cache as you can see by the missing disk cache section on the about:cache page.

Do you use built-in Firefox means or external cleanup software?

Does it has any effect if you refrain from clearing any data and just all all cookies as a test?

Create a new profile as a test to check if your current profile is causing the problem. Do not make any changes from the defaults before having tested this profile.

See "Creating a profile":

• https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

I use both native and add-on BetterPrivacy and Self-Destructing Cookies to clear cache and cookies.

Since disabling Hardware Acceleration I have not had a freeze. But the jury is still out for 2-3 weeks.

Almost a month and no freeze. So looks like it was Hardware Acceleration. My Macbook Retina also stopped freezing. So much for hardware abstraction and using advanced hardware functions.