This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

ค้นหาฝ่ายสนับสนุน

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

เรียนรู้เพิ่มเติม

Task manager says: "Firefox (41)"

  • 4 การตอบกลับ
  • 1 คนมีปัญหานี้
  • 8 ครั้งที่ดู
  • ตอบกลับล่าสุดโดย jscher2000 - Support Volunteer

more options

Hi, I don't understand what this means on task manager. My computer runs Windows 10. It lists "Firefox (41)" in the task manager with very high memory usage, although at the moment I have 9 tabs open. It doesn't change if I restart Firefox with fewer tabs. I've seen similar problems described elsewhere but I don't understand the solution given. I've seen something about finding "about:preferences" but I don't understand what that means. Is there a way to make this run better? Thanks.

Hi, I don't understand what this means on task manager. My computer runs Windows 10. It lists "Firefox (41)" in the task manager with very high memory usage, although at the moment I have 9 tabs open. It doesn't change if I restart Firefox with fewer tabs. I've seen similar problems described elsewhere but I don't understand the solution given. I've seen something about finding "about:preferences" but I don't understand what that means. Is there a way to make this run better? Thanks.

การตอบกลับทั้งหมด (4)

more options

In the Windows 10 Task Manager, you can expand the dialog to show more details, and then click the Details tab to view individual processes. If you click the Name column heading, the dialog will group all of the Firefox entries together. Each should have a Process ID (PID).

If you have tremendous patience, you can compare that with an internal list: type or paste about:processes in the address bar and press Enter to load that page.

If you have more Firefox processes in Windows than are listed on about:processes, there may be a second or hidden instance of Firefox running.

more options

If you notice you have more content processes than in the past then you may have Fission enabled. Fission is about a new site isolation architecture in Firefox and you will see more Firefox processes running than before and when Fission is enabled you can no longer limit the number of content processes in Settings or via dom.ipc.processCount on the about:config page. You can check the current Fission state on the "Help -> More Troubleshooting Information" (about:support) page (search for Fission).

more options

Thanks! So how can I improve how Firefox is running? I checked the about:processes list and there are far fewer than 41 items listed. Would this mean that there is a "hidden" instance of Firefox running? And if so how I can I fix that?

Based on the information on the about:support page, I believe Fission is running. Can I disable that? And is there any issue with doing so?

Sorry I don't understand this more intuitively...

more options

Are there still Firefox processes in the Windows Task Manager after you exit out of Firefox (closing out of the visible windows)?

If so, to investigate how they are starting, it is helpful to add the Command Line column to the Details tab. Right-click any column heading, click Select Columns, then check the box for Command Line.

A normal Firefox command line looks like one of these:

  • "C:\Program Files\Mozilla Firefox\firefox.exe"
  • "C:\Program Files (x86)\Mozilla Firefox\firefox.exe"

Do you see any with other startup parameters such as -P (to specify a profile) or -headless, etc.? Note that if your normal session of Firefox is running, you will see numerous child processes, so we are looking for ones that might explain how Firefox is starting in the background.