For DuckDuckGo, can you load their home page directly or does that also come up blank: https://duckduckgo.com/

If you can load their home page, does searching work from their search box or does that come up blank?

For Download.com, maybe it's related, I'm not sure. When you have a problem with one particular site, a good "first thing to try" is clearing your Firefox cache and deleting your saved cookies for the site.

(1) Clear Firefox's Cache

See: How to clear the Firefox cache

If you have a large hard drive, this might take a few minutes.

(2) Remove the site's cookies (save any pending work first). While viewing a page on the site, try either:

• right-click a blank area of the page and choose View Page Info > Security > "View Cookies"
• (menu bar) Tools > Page Info > Security > "View Cookies"
• click the padlock or globe icon in the address bar, then the ">" button, then More Information, and finally the "View Cookies" button

In the dialog that opens, download.com should be automatically filled in at the top. Then you can remove the site's cookies individually from the list below.

Then try reloading the page. Does that help?

If that doesn't help, could you test in Firefox's Safe Mode? In Safe Mode, Firefox temporarily deactivates extensions, hardware acceleration, and some other advanced features to help you assess whether these are causing the problem.

If Firefox is not running: Hold down the Shift key when starting Firefox.

If Firefox is running: You can restart Firefox in Safe Mode using either:

• "3-bar" menu button > "?" button > Restart with Add-ons Disabled
• Help menu > Restart with Add-ons Disabled

and OK the restart.

Both scenarios: A small dialog should appear. Click "Start in Safe Mode" (not Refresh).

Any improvement? (More info: Diagnose Firefox issues using Troubleshoot Mode)

Hi, sorry for delay in responding. For Duckduckgo, it is just the same if I do a search from the bar on their home page, I still get a blank screen.

There is a slight change today, which is that when I do a search from the FF search bar the results show on the screen for just a fraction of a second before it reverts to blank. That didn't happen yesterday.

I have tried FF Safe Mode, as you suggested, when Duckduckgo search works as it should, but after I exit Safe Mode it goes back to the blank screen.

I also cleared the Cnet / Download.com cookies as instructed, I was surprised at the number of them, but nothing changed. What should happen on that site when you click on Log In is a little window appears with fields for user name and password, but that does not show.

Thank you for the update.

When the page goes blank, does it make any difference if you force Firefox to "repaint" the page by resizing the window or using zoom to enlarge or reduce the text size?

Let's try to knock out a couple things:

(1) Try disabling nonessential or unrecognized extensions on the Add-ons page. Either:

• Ctrl+Shift+a
• "3-bar" menu button (or Tools menu) > Add-ons

In the left column, click Extensions. Then cast a critical eye over the list on the right side; none of these come with Firefox. If you can live without an extension for 24 hours, try disabling it.

Often a link will appear above at least one disabled extension to restart Firefox. You can complete your work on the tab and click one of the links as the last step.

Does that help?

(2) Try disabling Firefox from using hardware acceleration, which is a standard workaround for incompatibility with your system's graphics card/chipset driver software.

"3-bar" menu button (or Tools menu) > Options

In the left column, click Advanced. On the right side, with the "General" mini-tab active, uncheck the box for "Use hardware acceleration when available".

This takes effect the next time you exit Firefox and start it up again.

Any difference?

No difference with resizing page, or zooming in or out.

Disabling Extensions brought about a result! Of the five I have, I disabled three: Adguard Adblocker, Cookie Monster, and I don't care about cookies. I then tested Duckduckgo, which worked OK, I got a screen of results. Then I re-enabled the Extensions one by one, testing Duckduckgo each time. It still worked afterwards, with all of my Extensions enabled.

But.... when I exited FireFox and started it again, the search has gone back to showing a blank screen.

I have also checked FF hardware acceleration, it was already unchecked.

I don't think it's related to cookies if the page loads and then goes blank. Nor do I remember seeing ads on DuckDuckGo. Hmm...

Maybe your Firefox program files were damaged during the last update. That can cause random and seemingly inexplicable issues. For that we usually suggest:

Clean Reinstall

We use this name, but it's not about removing your settings, it's about making sure the program files are clean (no inconsistent or alien code files). As described below, this process does not disturb your existing settings. Do NOT uninstall Firefox, that's not needed.

(A) Download a fresh installer for Firefox 45.0 from https://www.mozilla.org/firefox/all/ to a convenient location. (Scroll down to your preferred language.) For maximum plugin compatibility, choose the 32-bit version.

(B) Exit out of Firefox (if applicable).

(C) Rename the program folder as follows:

(32-bit Firefox on 64-bit Windows)

C:\Program Files (x86)\Mozilla Firefox

to

C:\Program Files (x86)\OldFirefox

(Other systems)

C:\Program Files\Mozilla Firefox

to

C:\Program Files\OldFirefox

(D) Run the installer you downloaded in step (A). It should automatically connect to your existing settings.

Any improvement?

Note: Some plugins may exist only in that OldFirefox folder. If something essential is missing, look in these folders, but I suggest only copying what you recognize to be useful as there may be old junk in here:

• \OldFirefox\Plugins
• \OldFirefox\browser\plugins

Sorry, where do I need the new install to go? In its default \Mozilla Firefox, or in the renamed \OldFirefox ?

When you run the installer, allow it to use the default location, which will be C:\Program Files\Mozilla Firefox\

Correction: For 64-bit Windows, the default location for 32-bit Firefox is:

C:\Program Files (x86)\Mozilla Firefox\

Done as instructed, but no change I'm afraid. Duckduckgo search results still appear on screen very briefly before disappearing. If I disable and then re-enable any one of my Extensions at random, Duckduckgo will show results, until I exit FF, after which it does not work again. (Edit: At least I know now how to be able to use DDG when I want to! It was horrible having to go back to using Google!) Is it OK to uninstall \OldFirefox now? I notice they are both v. 45.0

If you aren't missing any plugins, sure, you can delete the OldFirefox folder.

This is an odd set of symptoms. The only other thing that comes to mind is: sometimes there is a problem in the files which store your extension lists. You can force Firefox to regenerate the files by doing the following:

Open your current Firefox settings (AKA Firefox profile) folder using either

• "3-bar" menu button > "?" button > Troubleshooting Information
• (menu bar) Help > Troubleshooting Information
• type or paste about:support in the address bar and press Enter

In the first table on the page, click the "Show Folder" button. This should launch a new window listing various files and folders in Windows Explorer.

Leaving that window open, switch back to Firefox and Exit, either:

• "3-bar" menu button > "power" button
• (menu bar) File > Exit

Pause while Firefox finishes its cleanup, then rename any of these files that you find:

• compatibility.ini to something like compatibility-old.ini
• extensions.ini to something like extensions-old.ini
• extensions.json to something like extensions-old.json
• extensions.sqlite to something like extensions-old.sqlite (might not exist depending on how long you've been using this settings folder)

When you start Firefox back up again, it should explore your profile folder, other folders, and the Windows registry to rebuild the list. It probably will ask you to approve some of the extensions. Once things settle down, could you check the Add-ons page again.

While you have the profile folder open: Do you have a chrome folder with a userContent.css customization file? If so, what kind of rules does it have in it?

I lost you a bit after exiting Firefox with the power button in the menu. Where were the compatibility and extensions files you listed meant to be? I did not see one of them. They are not in the Profiles folder. So I didn't rename anything, and Firefox restarted as normal. There is no chrome folder in the Profile folder.

Not in the Profiles folder (profiles plural) but in your active profile folder, which has a semi-random name. It would be quite strange for them not to be there.

Thank you. Names are now chaged as you suggest, but no difference in behaviour of DDG search, it still flashes results briefly then goes blank, while disabling/re-enabling any add-on still makes it work until I exit FF.

Sorry, I'm out of ideas at the moment.

Duckduckgo search is now working properly since FF updated to 45.0.1, though I'm prepared to accept it is a coincidence.

Download dot com login is still not working. I see from search results that the same sometimes happens on other browsers too, which suggests to me the problem is with Cnet and not FF. Either way, it's not the end of the world for me!

Thanks for all you did to help.