Are you saying that the back and forward buttons are permanently greyed out?

It's normal for them to be greyed out right after you clear the history because that's how the buttons work. If there is no history saved, the browser can't navigate back or forward because it doesn't know what pages to go to.

However, once you start navigating to different pages again, the back and forward buttons should work normally again.

The buttons are not permanently grayed out.

I didn't clear all the history, just the past 4 hours, looking in my history I can see the sites that I visited last night, but the sites that I visited this afternoon are gone (Which is what I wanted).

However, I had several windows open with lots of tabs and on all those tabs the back/forward buttons are grayed out (they weren't before).

There is a flaw in the time-based Clear Recent History function when it comes to session history -- open and closed tabs and windows: the only thing Firefox can do is completely remove those files.

If you need the old tabs badly:

Deleted File Recovery

A tool like Recuva can recover some erased files. This could be useful to track down recently removed session history files. Make sure Windows is set to show hidden files and folders:

• https://support.microsoft.com/en-us/help/14201/windows-show-hidden-files
• https://www.ccleaner.com/recuva

The typical files names for session history files are:

• recovery.jsonlz4
• recovery.baklz4
• previous.jsonlz4
• upgrade.jsonlz4-20191016161957 (the number varies, indicating the "build" that was installed)

To check the contents of a recovered file, you can drop it onto my page here:

https://www.jeffersonscher.com/ffu/scrounger.html

Do you have any that look to be worth reloading? Of course if you just need the URLs for reference, you can save the page of clickable links as an HTML file and open it in Firefox when needed.

Shadow Copies

You can use a utility program to search inside restore points to try to locate an old file that's usable. (Please do NOT try to use the built-in Windows System Restore for this because you probably would lose data.)

(1) Set Windows to show hidden files and folders:

https://support.microsoft.com/en-us/help/14201/windows-show-hidden-files

(2) Download and run one of these two programs:

• ShadowExplorer: http://www.shadowexplorer.com/
• System Restore Explorer: http://nicbedford.co.uk/software/systemrestoreexplorer/

Within the most recent restore point shown in the program, you can explore along this path to see whether you can find a shadow copy of your profile:

\Users\your-user-name\AppData\Roaming\Mozilla\Firefox\Profiles\

(3) Check in the sessionstore-backups folder of each profile for older backups. You can export interesting files to a convenient location such as your currently live desktop.

Any luck?

As you browse the web, Firefox helpfully remembers lots of information for you – sites you've visited, files you've downloaded and more. All of this information is called your history. However, if you are using a public computer or share a computer with someone, you may not want others to see these kinds of things.

This article explains what information is stored in your Firefox history and gives you step-by-step ways to clear all or part of it.

   To temporarily stop Firefox from storing history, see Private Browsing - Use Firefox without saving history.