A trusted site can break when Firefox's strict cookie defaults block what it needs to save. A session-only exception fixes that for one site: cookies stick until you quit Firefox, while the rule itself stays in place for next time.
You can set it three ways: the Manage Exceptions dialog with Allow for Session, the shield icon beside the address bar, or the Permissions tab in Page Info.
In this guide, I have covered:
Contents
Allow Cookies Temporarily for One Site in Firefox
Some sites need cookies simply to keep you signed in, hold a shopping cart, or remember a setting between visits. Firefox’s defaults lean strict here. Total Cookie Protection confines each site’s cookies to the site that set them, so a page that needs broader cookie access can look broken even when nothing else is wrong.
You don’t have to disable cookies everywhere or weaken your global tracking protections to fix it. Firefox supports per-site exceptions that grant one domain extra cookie access for the current session, and those cookies clear automatically when you close Firefox. Nothing changes for the rest of your sites.
The behavior is documented in Mozilla’s session cookie answers.
Use the Manage Exceptions dialog with Allow for Session
The closest match to a temporary cookie allowance is the Allow for Session entry in Firefox’s Manage Exceptions… list. The rule you add there persists across launches. Only the cookies get cleared when Firefox quits.
- Click
menu in the top-right of Firefox and choose Settings. - Select Privacy & Security from the left sidebar.
- In the Cookies and Site Data section, click the Manage Exceptions… button.
- Type the full site address (for example, https://example.com) in the Address of website field.
- Set the Status dropdown to Allow for Session (not plain Allow).
- Click Save Changes, then close the dialog.
- Reload the site in the browser.
Firefox now accepts cookies from that domain for this session and deletes them at shutdown. The exception rule stays in the list, so the same thing happens on your next launch. You’ll know it worked when the site signs you in and behaves normally for the rest of the session, then asks you to sign in again after you restart Firefox.
TIP: If the site already has a plain Allow exception and you want it temporary instead, open Manage Exceptions… again, click that row, and switch the dropdown to Allow for Session. Don’t add a second entry for the same site.
Turn off Enhanced Tracking Protection for that site
A faster route is to switch off Enhanced Tracking Protection for the one site you want to loosen. Unlike Allow for Session, cookies set while the shield is down stay saved until you clear them yourself.
- Open the website that fails to load in Firefox.
- Click the shield icon to the left of the address bar.
- Toggle the switch labeled "Enhanced Tracking Protection is ON for this site" so it moves to OFF.
- Wait for Firefox to reload the tab automatically, then try the page again.
With the shield off for that domain, Total Cookie Protection’s per-site boundaries lift and first-party cookies flow the way they did before ETP. Turn the shield back on from the same panel when you’re done.
This option isn’t time-limited. Cookies saved while the shield is off stay in Firefox’s storage until you clear them, even after the shield goes back on. If you want them cleaned up automatically at shutdown, use Allow for Session in Manage Exceptions… instead.
Set site cookie permissions from Page Info
If you’d rather not leave the page, the Permissions tab in Page Info exposes the same cookie control for the current site. It writes to the same underlying setting the address-bar shield and the Privacy & Security panel use.
- Right-click anywhere on the page and pick View Page Info.
- Click the Permissions tab at the top of the window that opens.
- Scroll to the Set Cookies row and uncheck Use Default so the value becomes clickable.
- Click Allow to grant persistent cookie storage, or pick a narrower value if that’s all you need.
- Close the Page Info window with to apply the change to this site.
Reload the page so the site picks up the new permission. This change sticks until you reverse it in Page Info, so pair it with a cookie cleanup if you only wanted temporary access.
The Permissions tab is covered in more depth in View Site Info and Set Site Settings in Firefox on the Computer.
What “Allow for Session” Actually Does
Picking Allow for Session changes two things at once, and it pays to know which is which. Set through Manage Exceptions…, the option behaves like two separate pieces working together:
- The cookies themselves get deleted the moment you quit Firefox.
- The exception rule stays saved, so the next launch accepts cookies from that site again and clears them when you close Firefox once more.
That split is what makes the setting temporary without any cleanup on your part. If you’d rather remove the rule entirely, the next section shows how.
If cookies are still surviving a restart even with a session rule in place, Firefox not clearing site data on close covers the usual causes.
ALERT: Treat Allow for Session as a guardrail against long-term tracking, not as a defensive control for the active browsing session. Any data saved during the session is still readable by site scripts, extensions, and any locally running software while Firefox is open.
How to Remove a Cookie Exception You No Longer Need
When a site no longer needs the extra room, remove the exception and it drops back under your normal Firefox cookie rules.
- Open
menu in the top-right of Firefox and pick Settings. - In the left sidebar, open Privacy & Security.
- Under Cookies and Site Data, click .
- Find the entry you want to remove. The search field at the top of the dialog filters the list.
- Click the row, then click to drop just that entry.
- Click to apply.
After saving, that domain is back under the same cookie rules as everything else your current Enhanced Tracking Protection level applies to. Total Cookie Protection and your other protections stay in place for the sites you haven’t listed explicitly.
Frequently Asked Questions
Does Allow for Session work in a private window?
Yes. Private windows drop their cookies when the window closes anyway, so the exception mostly matters when you move between regular and private modes in the same browser run, or visit the same site in both.
Will I stay signed in to a site set to Allow for Session?
No. Sign-in state usually lives in a session cookie, so quitting Firefox signs you out. The exception rule itself stays, and the sign-in prompt returns at your next launch.
How is this different from disabling cookies globally?
Disabling cookies affects every site you visit and stays that way until you turn them back on. An Allow for Session exception targets a single address, and Total Cookie Protection keeps working everywhere else.
The site still says cookies are blocked after I added an exception. Why?
It may need cookies from a subdomain, a third-party CDN, or cross-site identifiers that sit outside the per-site rule. Open Manage Exceptions… and add the extra domains the site lists, or turn off Enhanced Tracking Protection for that site so Firefox accepts cross-site cookies too.
Where do I view all the cookie exceptions I have set?
Everything you’ve added lives in Manage Exceptions… inside the Privacy & Security panel, in the order you added it. Each row shows the site’s address and its current permission (Block, Allow for Session, or Allow), so you can prune the list from one place.
