This might be relevant if you also installed Windows updates recent: If you haven't already, disable the Flash Player plugin's protected mode feature. See this support article from Adobe under the heading "Last Resort": Adobe Forums: How do I troubleshoot Flash Player's protected mode for Firefox?

To test whether Firefox 25.0.1 runs normally when it isn't using your personal data, could you do a two-minute experiment?

Create a new Firefox profile

It will have your system-installed plugins (e.g., Flash) and extensions (e.g., security software toolbars), but no other themes, extensions, or customizations. It also should have completely fresh settings databases and a fresh cache folder.

Exit Firefox and start up in the Profile Manager using Start > search box (or Run):

firefox.exe -P

Any time you want to switch profiles, exit Firefox and return to this dialog.

When creating a new profile, I recommend using the default location suggested, and to avoid data loss, not re-using any existing folder. Before deleting unneeded profiles, I suggest making a backup first in case something were to go wrong.

Does Firefox operate normally in the new profile?

If Firefox doesn't work normally in a new profile and you want to try Firefox 24 to see whether that will help, you can find a link to the installer in this article: Install an older version of Firefox.

You do not need to uninstall Firefox 25 before running the installer. If you do choose to uninstall Firefox 25, make sure NOT to remove all your personal data, since that would remove your bookmarks and any saved passwords.

One of the responses I got said:

This might be relevant if you also installed Windows updates recent: If you haven't already, disable the Flash Player plugin's protected mode feature. See this support article from Adobe under the heading "Last Resort": Adobe Forums: How do I troubleshoot Flash Player's protected mode for Firefox?

My response: Note that my crash / hangs are happening when I'm not running Flash. In fact, I removed Flash from my computer months ago due to concerns about it. So, I don't see how this could be my problem.

I tried creating a new profile. It's difficult to say whether that worked or not, since it didn't have any of my bookmarks, I couldn't really do much with it. The 3 or so minutes I did use it, it didn't crash. I switched to my original profile to be able to do some work.

You can export the bookmarks to an HTML file and import that file in the new profile or just open the file in a browser tab.

FYI, the "More System Details" info you provided with your post shows that the Flash Player plugin (Shockwave Flash) currently is installed.

If you would like to disable it as a test, you can do that on the Add-ons page. Either:

• Ctrl+Shift+a
• orange Firefox button (or Tools menu) > Add-ons

In the left column, click PLugins. Then set Shockwave Flash to "Never Activate".

Huh! I de-installed flash, and there is no such program listed in my program list from the control panel. Anyway, I turned it to "never activate."

Well, with Flash set to "never activate" this problem seemed to go away - until today. I've had to reboot my computer 3 times in the last 4 or 5 hours. This is a real PIA. And, a lot of videos aren't available without flash.

The thing I didn't try was to set up a new profile and import my bookmarks. That seems time consuming. . . . . Plus, I don't know where the bookmarks are stored and I don't have the time to research that.

Firefox stores the bookmarks and history is the places.sqlite database file.
Firefox also create a daily JSON backup for the bookmarks that is stored in the bookmarkbackups folder in the Firefox profile folder.

You can use this button to go to the Firefox profile folder:

• Help > Troubleshooting Information > Profile Directory: Show Folder (Linux: Open Directory; Mac: Show in Finder)
• http://kb.mozillazine.org/Profile_folder_-_Firefox

Did you check in the event viewer to see if you can identify that cause of the hangs?

Boot the computer in Windows Safe Mode with network support (press F8 on the boot screen) as a test to see if that helps.

Isn't there some way to just move back to version 25? It's 25.0.1 that seems to have started the problems.

There is hardly a difference between those two versions that would account for this issue.

• http://www.mozilla.org/en-US/firefox/25.0.1/releasenotes/
• http://www.mozilla.org/en-US/firefox/25.0/releasenotes/

If the computer hangs then this can only be a problem with one of the system drivers or services that run on your computer.

Does booting Windows in Safe mode has any effect like I suggested above?

This may not be related, but it keeps telling me that Adobe Acrobat needs upgrading, but when I ask to upgrade and go through the process, it continues to say I need to upgrade it. Could an old version be my problem, even though Firefox hangs when I'm not using it?

Hi sallye, regarding Adobe, I don't think it is causing your problem. But, for the sake of completeness: the Plugin Check site only recognizes the 11.x series of Acrobat/Reader as up-to-date. For some reason, Adobe does not offer that series to Vista users. To keep Adobe Acrobat/Reader X up-to-date (I think it is up to 10.1.8), I recommend using the Help > Check for Updates feature from within Adobe Acrobat/Reader instead of relying either on the Plugin Check site or Adobe's download page.

I didn't know about the event viewer. Interesting.

I get one of these:

Event ID 3013 for the Windows Search Service has been suppressed 240 time(s) since 11:21:13 PM. This event is used to suppress Windows Search Service events that have occurred frequently within a short period of time. See Event ID 3013 for further details on this event. Source: Search

Followed by a lot of these (with the info after "CACHE" different each time): The entry <C:\USERS\SALLY\APPDATA\LOCAL\MOZILLA\FIREFOX\PROFILES\N1V4E97R.DEFAULT-1385304802559\CACHE\C\55> in the hash map cannot be updated.

I do not use Windows much and have not used Vista asan Admin.

But my two cents whilst on a coffee break.

It sounds as if you have set Vista to index the Firefox cache folder. That is intended to speed up search results at the expense of needing indexing updates to be run. I do not think it is intended to be set to index cache file locations.

You should have options in the Windows control panel to set indexing locations. I have not got time to read up and search for an exact answer but maybe this helps

• http://windows.microsoft.com/en-gb/windows-vista/improve-windows-searches-using-the-index-frequently-asked-questions