Join the AMA (Ask Me Anything) with the Firefox leadership team to celebrate Firefox 20th anniversary and discuss Firefox’s future on Mozilla Connect. Mark your calendar on Thursday, November 14, 18:00 - 20:00 UTC!

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.

Avatar for Username

Search Support

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.

Learn More

This thread was archived. Please ask a new question if you need help.

Firefox randomly downloaded a file, with seemingly randomly name, that is 0 bytes and in download manager the source is moz-safe-about

grindart3
grindart3
more options

Hello, Firefox randomly downloaded a file, with seemingly randomly name, that is 0 bytes and in download manager the source is moz-safe-about. It happened when I was accessing a popular wiki site. I opened the file in notepad, it was empty. I put it on virus total and came back negative, as it is an empty file. I've curbed through the support tickets here, using the keyphrase 'moz-safe-about'. I understand this was/is quite a common problem, but it still makes me quite worried and left a sour taste in my mouth, as I haven't understood any of the explanations. I have enabled firefox to ask me whenever it wants to save something (I have no idea why this isnt the default state). Happened on a somewhat fresh, updated win 11 installation. I'm also attaching more information here with a picture. Long story short: should I be worried? Am I overreacting and this is just some sort of a bug that occurred while getting a sites data? Thank you for your time.

Hello, Firefox randomly downloaded a file, with seemingly randomly name, that is 0 bytes and in download manager the source is moz-safe-about. It happened when I was accessing a popular wiki site. I opened the file in notepad, it was empty. I put it on virus total and came back negative, as it is an empty file. I've curbed through the support tickets here, using the keyphrase 'moz-safe-about'. I understand this was/is quite a common problem, but it still makes me quite worried and left a sour taste in my mouth, as I haven't understood any of the explanations. I have enabled firefox to ask me whenever it wants to save something (I have no idea why this isnt the default state). Happened on a somewhat fresh, updated win 11 installation. I'm also attaching more information here with a picture. Long story short: should I be worried? Am I overreacting and this is just some sort of a bug that occurred while getting a sites data? Thank you for your time.
Attached screenshots

All Replies (3)

cor-el
cor-el
  • Moderator
  • Top 10 Contributor
more options

Getting zero-byte .htm files can be caused by downloading a file over an insecure HTTP link from a secure HTTPS page (i.e. mixed content is on the page) or by Firefox sending a HTTP background request in HTTPS-Only mode and "dom.block_download_insecure = true" in about:config.

You can look at these prefs in about:config:

  • dom.security.https_only_mode_send_http_background_request
  • dom.block_download_insecure
grindart3
grindart3 Question owner
more options

cor-el said
Getting zero-byte .htm files can be caused by downloading a file over an insecure HTTP link from a secure HTTPS page (i.e. mixed content is on the page) or by Firefox sending a HTTP background request in HTTPS-Only mode and "dom.block_download_insecure = true" in about:config. You can look at these prefs in about:config:
  • dom.security.https_only_mode_send_http_background_request
  • dom.block_download_insecure

I see. Do you think this whole thing is somehow malicious, and that I should worry about it, or it's just an annoyance? and by downloading, you just mean loading a page, correct? As I have not intended to download anything

coffeelover101011
coffeelover101011
more options

I got this exact problem visiting the official python documentation: https://docs.python.org/3/library/queue.html

I don't understand the answer posted on this site; it doesn't add up for me.