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pdf is continuing to auto download despite being set only to open

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I have it set in setting to open in Firefox. it is continuing to automatically download all PDFs and it is eating into my data! please help. I have to get this to stop or I will no longer be able to click on any PDFs with Firefox anymore. I have also tried setting it to always ask, but if I do that and then tell it to open, then it STILL DOWNLOADS THE FILE! I cannot understand why anyone would ever want files they just wanted to read to just randomly download. I am a genealogy researcher and used to click on dozens of PDFs a day to read, now I can't with Firefox or I won't have internet for half the month after I use up my data. There has to be someway to stop this, I don't like other browsers, but right now, if it involves a PDF I have to use a different browser. (also quite annoying to have to delete multiple files that I never wanted to download - I was using Firefox to pay a bill and downloaded it SIX times) Please help!

I have it set in setting to open in Firefox. it is continuing to automatically download all PDFs and it is eating into my data! please help. I have to get this to stop or I will no longer be able to click on any PDFs with Firefox anymore. I have also tried setting it to always ask, but if I do that and then tell it to open, then it STILL DOWNLOADS THE FILE! I cannot understand why anyone would ever want files they just wanted to read to just randomly download. I am a genealogy researcher and used to click on dozens of PDFs a day to read, now I can't with Firefox or I won't have internet for half the month after I use up my data. There has to be someway to stop this, I don't like other browsers, but right now, if it involves a PDF I have to use a different browser. (also quite annoying to have to delete multiple files that I never wanted to download - I was using Firefox to pay a bill and downloaded it SIX times) Please help!

Chosen solution

Hi Biscuit, Firefox can't display content without downloading it, whether that is a PDF, a web page, an image, etc. You can tweak some hidden settings to determine where Firefox saves the file, whether that is the web content cache, the "Save files to:" download folder, or the Windows Temp folder, but either way, you'll get the data hit.

I would be surprised if other browsers don't need to download a PDF to display it.


Background: inline vs. attachment disposition

If web servers don't specify how Firefox should handle a PDF, or specify "inline" handling, then then Firefox loads the PDF as web content with its original URL in the address bar. The PDFs are saved with other cached web content, not in your download folder.

But web servers can try to force a download by setting Content-Disposition: attachment if they don't want browsers to show the files in a tab. Firefox changed what it does in this case:

Before Firefox 98: Firefox always showed a download dialog, even though you had already told Firefox what you wanted to do, even when you checked the box to always do this in the future. It was kind of infuriating.

Firefox 98+: Firefox downloads the file automatically and then opens it. Because these are saved to disk the URLs start with file:///. By default, they are saved in your "Save files to" folder on the Settings page.

New options for saving downloads

In response to user suggestions/complaints, Mozilla added some options to modify the above:

(1) Just for PDFs, override "attachment" disposition to "inline"

When your handling action is "Open in Firefox", all PDFs will be opened as web content and saved in the cache instead of a regular folder. Here's how you set this up:

(a) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button accepting the risk.

More info on about:config: Configuration Editor for Firefox. The moderators would like us to remind you that changes made through this back door aren't fully supported and aren't guaranteed to continue working in the future. I'm using this so I feel comfortable mentioning it.

(b) In the search box in the page, type or paste browser.download.open_pdf_attachments_inline and pause while the list is filtered -- requires Firefox 103 or later

(c) Double-click the preference to switch the value from false to true

(2) For all the downloads Firefox saves to disk and opens automatically, change from the "Save files to" folder to the Windows Temp folder

Here's how you access it:

(a) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button accepting the risk.

More info on about:config: Configuration Editor for Firefox. The moderators would like us to remind you that changes made through this back door aren't fully supported and aren't guaranteed to continue working in the future.

(b) In the search box in the page, type or paste browser.download.start_downloads_in_tmp_dir and pause while the list is filtered -- requires Firefox 102 or later

(c) Double-click the preference to switch the value from false to true

This would not affect files opened with inline disposition; those will still be in the web content cache.

Hopefully some of that gets Firefox working the way you want.

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All Replies (5)

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Chosen Solution

Hi Biscuit, Firefox can't display content without downloading it, whether that is a PDF, a web page, an image, etc. You can tweak some hidden settings to determine where Firefox saves the file, whether that is the web content cache, the "Save files to:" download folder, or the Windows Temp folder, but either way, you'll get the data hit.

I would be surprised if other browsers don't need to download a PDF to display it.


Background: inline vs. attachment disposition

If web servers don't specify how Firefox should handle a PDF, or specify "inline" handling, then then Firefox loads the PDF as web content with its original URL in the address bar. The PDFs are saved with other cached web content, not in your download folder.

But web servers can try to force a download by setting Content-Disposition: attachment if they don't want browsers to show the files in a tab. Firefox changed what it does in this case:

Before Firefox 98: Firefox always showed a download dialog, even though you had already told Firefox what you wanted to do, even when you checked the box to always do this in the future. It was kind of infuriating.

Firefox 98+: Firefox downloads the file automatically and then opens it. Because these are saved to disk the URLs start with file:///. By default, they are saved in your "Save files to" folder on the Settings page.

New options for saving downloads

In response to user suggestions/complaints, Mozilla added some options to modify the above:

(1) Just for PDFs, override "attachment" disposition to "inline"

When your handling action is "Open in Firefox", all PDFs will be opened as web content and saved in the cache instead of a regular folder. Here's how you set this up:

(a) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button accepting the risk.

More info on about:config: Configuration Editor for Firefox. The moderators would like us to remind you that changes made through this back door aren't fully supported and aren't guaranteed to continue working in the future. I'm using this so I feel comfortable mentioning it.

(b) In the search box in the page, type or paste browser.download.open_pdf_attachments_inline and pause while the list is filtered -- requires Firefox 103 or later

(c) Double-click the preference to switch the value from false to true

(2) For all the downloads Firefox saves to disk and opens automatically, change from the "Save files to" folder to the Windows Temp folder

Here's how you access it:

(a) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button accepting the risk.

More info on about:config: Configuration Editor for Firefox. The moderators would like us to remind you that changes made through this back door aren't fully supported and aren't guaranteed to continue working in the future.

(b) In the search box in the page, type or paste browser.download.start_downloads_in_tmp_dir and pause while the list is filtered -- requires Firefox 102 or later

(c) Double-click the preference to switch the value from false to true

This would not affect files opened with inline disposition; those will still be in the web content cache.

Hopefully some of that gets Firefox working the way you want.

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thank you for taking your time to answer. I will try this. This just started happening on my computer with the last update and it has been driving me nuts! I have deleted countless numbers of files that I never wanted. Thanks again for the instructions and explanation!

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Hello,

I am glad to hear that your problem has been resolved. If you haven't already, please select the answer that solves the problem. This will help other users with similar problems find the solution.

Thank you for contacting Mozilla Support.

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Chrome > Settings > Privacy & Security > Site Settings > Additional Content Settings > PDF Documents > UNCHECK Download PDF files instead of automatically opening them in Chrome.

Hope You Find This Useful, Peter

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petergroft said

Chrome > Settings > Privacy & Security > Site Settings > Additional Content Settings > PDF Documents > UNCHECK Download PDF files instead of automatically opening them in Chrome. Hope You Find This Useful, Peter

Hi Peter, this is the Firefox forum, so steps for Chrome browsers are not really relevant here.