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Mp4 and gifv videos won't play in FF59

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For some reason in the last few weeks some videos, I think MP4 and gifv files won't play. The videos will start to load and then it will freeze and won't play at all. Youtube videos seem to work fine. I've tried completely uninstalling FF (including all appdata folders for FF) and reinstalling, running in FF safe mode, turning off hardware acceleration, etc. and none of those work. I have no clue what's happening.

For some reason in the last few weeks some videos, I think MP4 and gifv files won't play. The videos will start to load and then it will freeze and won't play at all. Youtube videos seem to work fine. I've tried completely uninstalling FF (including all appdata folders for FF) and reinstalling, running in FF safe mode, turning off hardware acceleration, etc. and none of those work. I have no clue what's happening.

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Make sure you are not blocking content.

Start Firefox in Safe Mode {web link} by holding down the <Shift> (Mac=Options) key, and then starting Firefox.

A small dialog should appear. Click Start In Safe Mode (not Refresh). Is the problem still there?


One issue that seems more common lately is Firefox's Tracking Protection feature. When it is blocking content in a page, a shield icon will appear at the left end of the address bar next to the padlock icon. This article has more info on managing this feature: Tracking Protection {web link}

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Okay here's what the console says, I have no idea what any of it means though.

Could not write session state file Object { operation: "move", path: "C:\Users\Jason\AppData\Roaming\Mozi…", winLastError: 2, stack: "", fileName: "(unknown module)", lineNumber: undefined } SessionFile.jsm:416 Could not write session state file Object { operation: "move", path: "C:\Users\Jason\AppData\Roaming\Mozi…", winLastError: 2, stack: "", fileName: "(unknown module)", lineNumber: undefined } SessionFile.jsm:416 The resource at “https://www.facebook.com/plugins/like.php?href=https%3A%2F%2Ffacebook.com%2Fimgur&width&layout=button&action=like&show_faces=false&share=false&height=35” was blocked because tracking protection is enabled.[Learn More] dkHl5vc Loading failed for the <script> with source “https://s.imgur.com/min/advertising.js?1526508494”. dkHl5vc:561 Loading failed for the <script> with source “https://c.amazon-adsystem.com/aax2/apstag.js”. dkHl5vc:1 Loading failed for the <script> with source “https://s.imgur.com/min/px.js?ch=2”. dkHl5vc:572 Loading failed for the <script> with source “https://z.moatads.com/imgurcontent786409209796/moatcontent.js#l1=imgur.com&l2=Epic!&l3=__page__&l4=-&zmoatab_cm=0&t=1526533152944&de=627466619325&zMoatAB_SNPT=true&vc=2”. dkHl5vc:1 The resource at “https://www.google-analytics.com/analytics.js” was blocked because tracking protection is enabled.[Learn More] dkHl5vc Loading failed for the <script> with source “https://www.google-analytics.com/analytics.js”. dkHl5vc:1 The resource at “https://platform.twitter.com/widgets.js” was blocked because tracking protection is enabled.[Learn More] dkHl5vc Loading failed for the <script> with source “https://platform.twitter.com/widgets.js”. dkHl5vc:1 The resource at “https://sb.scorecardresearch.com/beacon.js” was blocked because tracking protection is enabled.[Learn More] dkHl5vc Loading failed for the <script> with source “https://sb.scorecardresearch.com/beacon.js”. dkHl5vc:1 The resource at “https://secure.quantserve.com/quant.js” was blocked because tracking protection is enabled.[Learn More] dkHl5vc Loading failed for the <script> with source “https://secure.quantserve.com/quant.js”. dkHl5vc:1 The resource at “https://connect.facebook.net/en_US/fbevents.js” was blocked because tracking protection is enabled.[Learn More] dkHl5vc Loading failed for the <script> with source “https://connect.facebook.net/en_US/fbevents.js”. dkHl5vc:1 Loading failed for the <script> with source “https://www.googletagservices.com/tag/js/gpt.js”. under_sidebar:13 Loading failed for the <script> with source “https://c.amazon-adsystem.com/aax2/apstag.js”. under_sidebar:1 Loading failed for the <script> with source “https://www.googletagservices.com/tag/js/gpt.js”. pop_sky:13 Loading failed for the <script> with source “https://c.amazon-adsystem.com/aax2/apstag.js”. pop_sky:1 The resource at “https://tags.crwdcntrl.net/c/12316/cc.js?ns=_cc_12316” was blocked because tracking protection is enabled.[Learn More] dkHl5vc Loading failed for the <script> with source “https://tags.crwdcntrl.net/c/12316/cc.js?ns=_cc_12316”. dkHl5vc:1 Loading failed for the <script> with source “https://www.googletagservices.com/tag/js/gpt.js”. top_banner:13 Loading failed for the <script> with source “https://c.amazon-adsystem.com/aax2/apstag.js”. top_banner:1

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Did you check for issues caused by Tracking Protection and clicked the the shield icon on the location bar to disable Tracking Protection?

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Yeah and it still won't play. The video will play for a couple secs hen stop, but the bar on the video moves like it's still playing. BTW, I also temporarily shutoff my entire firewall/antivirus just to check and it wasn't the problem.