Firefox hangs on browser history clearing...can I do anything about it?

Question

There's about 7 months worth of browsing history in my Firefox profile. Trying to clear it "entirely" is giving me trouble, even in safe mode. Cache, cookies, and everything '''else''' clears fine in a small amount of time. I'm writing this question in Chrome as we speak because Firefox is currently unusable.
The problem is with clearing browser history (only on time setting "everything") specifically because Firefox will hang (and entirely freeze the GUI) until I decide to manually kill it in the task manager. The firefox.exe process shows a curious, steady 13% cpu utilization during this task on a core i7-920 cpu. Same result in safe mode. Same result if I try to set the browser history clearing settings "when I close Firefox" -- Firefox will indeed close but still be listed in the task manager taking up a 13% cpu utilization and refuses to open again until I manually kill it. So far I've waited for around an hour for the process to complete but honestly though, the task of "deleting 7 months worth of browsing history" should only takes seconds...possibly "minutes" maximum on a mid-range PC, no?
Some additional info on my machine: it's custom built from 2009 but it still performs strongly. Not too long ago I upgraded to a Samsung 840 Pro SSD and this is where the Firefox profile is on. Even though I only have 6GB of RAM, I still enable "Rapid Mode" in Samsung Magician. That process will chew through 5-6GB fairly easily, but it's still a noticeable speed increase over my native SATA II chipset limitation on my motherboard. Intel's ICH10R raid controller is a bit dated, but it works (mostly) and gives me a cheap raid1 solution for a couple of existing storage drives in my system (they're not related to the OS drive anyway.) I have set the recommended amount of 10% over-provisioning on the SSD. I keep a very close eye on the software I chose to execute so I'm fairly confident that there isn't anything else (hardware '''or''' software related) "slowing down" the system. Drivers/Win7 x64/Firefox 33 are all up to date (even running on "legacy" status now with my GPU drivers.) I do have a probably "more than average" number of extensions and custom scripting via Greasemonkey...I also have quite a bit of customization on Reddit from the "Reddit Enhancement Suite" tool -- so I wouldn't be surprised if "more than average" customization somehow corrupted the '''places.sqlite''' file and this is the explanation for my current troubles. I get rid of unnecessary plugins like Java but there's some you can't really mess with like Google's "update" plugin that's automatically installed if you have Chrome installed on your system for example.
So, after talking about all of that, let's talk about some realistic options. I could "reset" back to a factory Firefox installation but I would need to backup all of my extension data so I'm hoping that's a "last resort." What do you think about these options:
1. Letting the task run all night and see if it actually finishes in the morning, even if it's only using 13% cpu.
2. Following this option: https://support.mozilla.org/en-US/questions/1004992#answer-587688 where you simply manually delete the places.sqlite file (and then hope all your extensions are still intact -- considering that was posted for Firefox 29.) Backing up bookmarks is no issue but I would really feel worried that "other settings" would go with this file.
3. I '''could''' temporarily take my storage raid1 offline as Intel's raid controller and its limited bios memory is likely the biggest bottleneck in my system. However I would probably risk blue-screening on Windows startup as I don't know how the OS would react to such a traumatic change in SATA configuration type from "RAID" to "AHCI"...plus the Intel Matrix Storage Console is (I believe) no longer in development so it would probably break too and I would probably somehow end up losing the raid volume, something I'd rather avoid than "experiment with." I wish Samsung Magician was able to do more with the SSD SATA connection and not let it revert to a legacy "perhaps IDE-like" mode (it doesn't detect bios raid modes) but I guess there's only so many things a 2009 motherboard can do.
4. Your suggestions?
I think the main thing I learned from all this is to be sure to clean your history/cache on a regular basis and don't let it build up like I did. I had operated for some time knowing that it would be nice to keep a history of every site I visited because I could go back and look at specific times for when I visited associated sites as sort of "online diary" to see how I spend my time throughout the months. Turns out I paid the price for this assumption.

Answer 1

Hello
Certain Firefox problems can be solved by performing a ''Clean reinstall''. This means you remove Firefox program files and then reinstall Firefox. Please follow these steps:
'''Note:''' You might want to print these steps or view them in another browser.
#Download the latest Desktop version of Firefox from http://www.mozilla.org and save the setup file to your computer.
#After the download finishes, close all Firefox windows (click Exit from the Firefox or File menu).
#Delete the Firefox installation folder, which is located in one of these locations, by default:
#*'''Windows:'''
#**C:\Program Files\Mozilla Firefox
#**C:\Program Files (x86)\Mozilla Firefox
#*'''Mac:''' Delete Firefox from the Applications folder.
#*'''Linux:''' If you installed Firefox with the distro-based package manager, you should use the same way to uninstall it - see [[Installing Firefox on Linux]]. If you downloaded and installed the binary package from the [http://www.mozilla.org/firefox#desktop Firefox download page], simply remove the folder ''firefox'' in your home directory.
#Now, go ahead and reinstall Firefox:
##Double-click the downloaded installation file and go through the steps of the installation wizard.
##Once the wizard is finished, choose to directly open Firefox after clicking the Finish button.
More information about reinstalling Firefox can be found [[Troubleshoot and diagnose Firefox problems#w_5-reinstall-firefox|here]].
<b>WARNING:</b>Do not use a third party uninstaller as part of this process. Doing so could permanently delete your [[Profiles|Firefox profile]] data, including but not limited to, extensions, cache, cookies, bookmarks, personal settings and saved passwords. <u>These cannot be easily recovered unless they have been backed up to an external device!</u> See [[Back up and restore information in Firefox profiles]]. <!-- Starting in Firefox 31, the Firefox uninstaller no longer lets you remove user profile data.Ref: Bug 432017 and https://support.mozilla.org/kb/uninstall-firefox-from-your-computer/discuss/5279 [Fx31] Windows uninstaller will no longer offer the option to remove personal data -->
Please report back to say if this helped you!
Thank you.