After that, you can restart Firefox and all is working again. The problem is, that I already did all that but once you have installed BetterPrivacy one time, it screws up your configuration somehow for good even when you already uninstalled the addon and/or tried Firefox safe mode.Īnyway, the fix for this is uninstall BetterPrivacy, close Firefox AND delete the Firefox prefs.js file. Now I can imagine someone might think 'duh you could have figured that out easily by starting Firefox in safe mode and/or uninstalling your addons in your troubleshooting process'. Long story short, this problem is caused by the BetterPrivacy addon.

After the reinstall, I did my normal post installation routine: install addons, settings tweaks, about:config tweaks.Īfter that. So I did a reinstall and everything worked fine again.

pdf file and the exact same issue occurred which made me think that there was something else going on. Also, I do have flash installed and flash sites and videos work perfectly fine.Įdit: uploading screenshots to this site doesn't seem to work so I hosted my screenshot on imgur: Īfter a lot of troubleshooting, I found the culprit of this problem: The files itself are not corrupt and work fine in Edge browser. swf files but Firefox doesn't want to open them. I also tried to see if deleting the mimeTypes.rdf file from the Firefox profiles folder makes any difference but that doesn't help either. swf without asking, but that gives me flashback nightmares from 15 years ago when popup blockers weren't that common: Firefox loops and creates an infinites number of tabs while not actually opening the. swf extension in the Firefox settings to always open.

Because of this behaviour, I tried to manually set the. swf file, Firefox asks me if I wish to open the file (see attached screenshot), then when I click Open with Firefox and the OK button it just re-prompts me again with the same question (same as screenshot). swf files stored on the local computer anymore. I believe since last update, Firefox won't open.

Swf viewer online firefox