Your System Details shows; Mozilla/5.0 (Windows NT 10.0 and MacOS Sierra

What's your computer system and Firefox version?

https://support.mozilla.org/en-US/kb/update-firefox-latest-version?cache=no Did you update Firefox to the latest version 66.0.4 May 5, 2019 Fixes add-on certificate issue. 66.0.5 May 7, 2019 Further improvements to re-enable web extensions

Start Firefox in Safe Mode {web link}

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

FredMcD said

Your System Details shows; Mozilla/5.0 (Windows NT 10.0 and MacOS Sierra What's your computer system and Firefox version? https://support.mozilla.org/en-US/kb/update-firefox-latest-version?cache=no Did you update Firefox to the latest version 66.0.4 May 5, 2019 Fixes add-on certificate issue. 66.0.5 May 7, 2019 Further improvements to re-enable web extensions

I'm reporting it from a browser on a Windows box, but it's on the Mac that I'm having a problem. I tried to remove the system data that was auto-generated, but apparently it just added to it.

The problem was long before the certificate and extensions issue, so I'm positive the updates won't address this. I'll try in safe mode to see what happens. I'll have to wait to make sure things aren't just working for the first few minutes after opening.

Thinking back, it's possible this came about after restoring my Mac from Time Machine after a crash. I know it was some time afterward that it happened, but I don't recall that it was immediate.

ETA: I tried in safe mode, and it has the same problems.

I have now also applied those updates, just to clarify. The problem still exists with the updates - with and without safe mode.

You can check the Web Console (Tools -> Web Developer) for messages about blocked content and about the presence of mixed or unsafe content.

• https://developer.mozilla.org/en-US/Tools/Web_Console

You can check the Network Monitor to see if content is blocked or otherwise fails to load.

• https://developer.mozilla.org/en-US/Tools/Network_Monitor

If necessary use "Ctrl+F5" or "Ctrl+Shift+R" (Mac: Command+Shift+R) to reload the page and bypass the cache to generate a fresh log.

If you use extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) that can block content (Adblock Plus, NoScript, Disconnect, Ghostery, Privacy Badger, uBlock Origin) always make sure such extensions do not block content.

• make sure your extensions and filters are updated to the latest version
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

Firefox shows the shield icon at the left end of the location/address bar in case Content Blocking is blocking content.

• click the shield icon for more detail and possibly disable the protection

You can check the Web Console about what content is blocked

• "3-bar" menu button or Tools -> Web Developer
• https://support.mozilla.org/en-US/kb/tracking-protection
• https://support.mozilla.org/en-US/kb/content-blocking

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 the Cookies from websites that cause problems via the "3-bar" Firefox menu button (Options/Preferences).

"Remove the Cookies" from websites that cause problems:

• Options/Preferences -> Privacy & Security
  Cookies and Site Data -> Manage Data

"Clear the Cache":

• Options/Preferences -> Privacy & Security
  Cookies and Site Data -> Clear Data -> Cached Web Content: Clear

Start Firefox in Safe Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration is is causing the problem.

• switch to the DEFAULT theme: "3-bar" menu button or Tools -> Add-ons -> Themes
• do NOT click the "Refresh Firefox" button on the Safe Mode start window

• https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

You can remove all data stored in Firefox from a specific domain via "Forget About This Site" in the right-click context menu of an history entry ("History -> Show All History" or "View -> Sidebar -> History").

Using "Forget About This Site" will remove all data stored in Firefox from this domain like history and cookies and passwords and exceptions and cache, so be cautious. If you have a password or other data from that domain that you do not want to lose then make sure to backup this data or make a note.

You can't recover from this 'forget' unless you have a backup of involved files.

If you revisit a 'forgotten' website then data from that website will be saved once again.

• https://support.mozilla.org/en-US/kb/delete-browsing-search-download-history-firefox

Force-refresh doesn't work. I tried it lots of times.

It's not blocked content or add-ons. Everything loads fine in private browsing, and I have tried with all add-ons turned off.

I have tried forgetting sites, clearing the cache, deleting cookies, and manually deleting the cache/cookie files to force them to be re-created.

Same issues were present in safe mode.

Again, everything works fine in private browsing sessions, but I don't want to use private browsing for everything (I like having some info saved).

Are there any messages in the Web Console about blocked content?

• "3-bar" menu button or Tools -> Web Developer

You can check the Web Console (Tools -> Web Developer) for messages about blocked content and about the presence of mixed or unsafe content.

• https://developer.mozilla.org/en-US/Tools/Web_Console

You can check the Network Monitor to see if content is blocked or otherwise fails to load.

• https://developer.mozilla.org/en-US/Tools/Network_Monitor

If necessary use "Ctrl+F5" or "Ctrl+Shift+R" (Mac: Command+Shift+R) to reload the page and bypass the cache to generate a fresh log.

I don't see blocked content messages, but I see it is throwing some exceptions of this form: Exception { name: "NS_ERROR_FILE_CORRUPTED" ... (with references to javascript files from the domain I'm trying to access)

I googled that exception and saw that it can be an issue with storage.sqlite. I removed it and so far it seems to be working.

Thank you for directing me to the web console! This makes sense now for why it worked in private mode.

I spoke too soon, as it is still causing issues on other sites. The same NS_ERROR_FILE_CORRUPTED exception. Are there other files I should remove to reset this?