Hi, thank you for all of these pieces of information. Have you tried to delete cookies and other information for these websites?

• Delete cookies to remove the information websites have stored on your computer

Yes, tried just about everything. The problem is definitely somewhere in the profile folder!

Any new profile created does not exhibit the problem! Starting Firefox in safe mode has no effect either. So it is definitely some were in the profile that some code got changed or is missing in some file. But which and where?

The most obvious error is first and foremost Firefox does not remember its window size. However, it appears to remember if it's positioned on the left or on the right side of the screen.

Secondary, Flash contents on some websites does not play (First observed on BBC.com) and an error message is produced Claiming the need to install flash player despite that it is installed as the latest newest version.

Yes I have tried that deleting all the cookies and information the relevant websites stored and it has no effect. The error remains and is specifically related to the information contained in a profile folder.

HI, Could you please use the Adobe Flash Uninstaller and remove flash https://helpx.adobe.com/flash-player/kb/uninstall-flash-player-windows.html I did not book mark the page but BBC uses both Flash and HTML5 on their pages and it lets the browser choose which one to use. Could you give that a try on BBC with ot flash please to see if you are having problems still. This if you do have problems confirms it is Firefox. You can get new release Flash this date from here after : https://get.adobe.com/flashplayer/otherversions/ Step 1: Select Operating System Step 2: Select A Version (Firefox, Win IE . . . .) Note: Other software is offered in the download. <Windows Only>

As for the re-sizing windows hang in there for someone else to respond. Please respond to how BBC works without Flash installed. Thanks.

The oddity is that FF in this one particular profile, which happens to be my main profile, does not store/record or read window size but it also has on some websites and issue with flash player. Coincidentally or not, both of the websites I have noticed it are news websites: BBC.com and ABC.com This might be Caused by the same issue.

The question is in which file does Firefox read its startup window size and if it has flash player installed or not and why does it not remember the window size and appears to certain websites not having a flash player installed!?

Profile folders contain a lot of files. Most custom settings are stored in prefs.js' which is the disk-based version of the modified preferences you see in about:config (if you have ever opened the about:config page in Firefox). Do you want to try to rule that out?

You can open your currently active 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 "Open 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 prefs.js to OLDprefs.js. By default, Windows does not show the .js extension, but says it is a JScript file. For greater accuracy in file operations, you can set Windows to show all file extensions. See: https://www.bleepingcomputer.com/tutorials/how-to-show-file-extensions-in-windows/

Start Firefox back up again and it should generate a new prefs.js file with just the basic defaults (Firefox and extensions will make changes over time). Are either of the problems solved?

To reverse this operation so you can get your preferences back, you'll follow the same steps as above except: (A) delete the prefs.js file created for testing, and (B) rename OLDprefs.js back to prefs.js.

I did all that more or less by creating different profiles. The phenomenon remains the same, in the new profile respectively Pref.js the problem is not present. only in my main profile the problem is. frustrating.

dorcom said

I did all that more or less by creating different profiles. The phenomenon remains the same, in the new profile respectively Pref.js the problem is not present. only in my main profile the problem is. frustrating.

I think you're saying that you are not going to try my suggestion?

Unless someone comes along and tells us exactly where the problem setting is, I think an "elimination" approach of knocking out individual files and seeing whether it helps is the logical next step.

My first sentence in my reply is perhaps not very clear. I meant to say I did all that and more as well as creating also different profiles. As a former IT guy I have applied just about all the tricks in the book I know and I am aware of. I do have to admit I'm a little bit confused by your term and a reference of the "3- bar" menu button.

in any case I know where the profile is stored and I did rename it. of course it starts up with the issue gone but of course so are gone all the preferences.

I tried the same approach with the xulstore.json file, same thing. I did even do a file contents comparison and could not find anything that is obviously different indicating that Firefox should not remember its previous window size and when it comes to certain websites not to play flash appearing to the website as if the flash player is not installed.

What remains is still the same question, what particular setting is it and where that causes this behavior/problem?

it increasingly appears the only choice I have is to create a new profile and completely rebuilt all. This of course is a brute force approach of sorts. Compared to a home this would mean if the front door sticks, I throw out all the furniture and tear down half the house....

Okay, my reading comprehension seems to be low this morning. Could you clarify very exactly --

In your normal profile:

(1) Temporarily removing the xulstore.json file and having Firefox create a new one at the next startup DID NOT resolve the issue. (According to your original post.)

(2) Temporarily removing the prefs.js file and having Firefox create a new one at the next startup DID or DID NOT resolve the issue?

By "3-bar" menu button I mean the button with three horizontal stripes that usually appears at the right end of the main toolbar and displays the application menu with the large icons.

Perhaps it would make sense to copy selected files and folders a couple at a time from your normal profile to the new one and see what happens. This article describes the key files: Recovering important data from an old profile.

EUREKA! I nailed it, kind of, sort of....

With 100% certainty the culprit is exclusively somewhere in the prefs.js! It will take time to find which line of code it is that does it or that is missing.

Since I'm a backup guru/preacher I went back to a time where Firefox was running just perfectly: December 10, 2016

I extracted one file (prefs.js) and dumped it into my current normal profile. BINGO! FF remembers the size again and flash videos on BBC or ABC work!

So now Sherlock Holmes, it is elementary my dear Watson which of the 857 lines of code/configuration in the prefs.js file it is or is missing that causes this peculiar problem!

As I believed to recall this problem appeared to happen after a Firefox update but I'm not 100% sure.

If you place the prefs-good.js and prefs-bad.js files side-by-side in a folder you can use WinMerge (or your favorite text file comparison tool) to compare them. Lots of noise in such a comparison due to Firefox recording dates and extensions recording preferences, but maybe you can find a few candidates for further investigation.