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Only display fully downloaded files in the download folder

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Hello dear community,

I have a program that continuously monitors the download folder under Windows 11 for a specific file and retrieves it. I download this file in Firefox, but the said program gives an error.

I have noticed that when files are downloaded in FireFox, they already appear in the Downloads folder with the corresponding file extension with 0 bytes and these are then apparently swapped or merged with the .parts file.

The problem is that the mentioned program now tries to retrieve the unfinished file, which then leads to an error.

Does anyone know if it is possible to customize Firefox so that the file only appears in the download folder when the download is fully complete?

Many thanks for your help :D

Hello dear community, I have a program that continuously monitors the download folder under Windows 11 for a specific file and retrieves it. I download this file in Firefox, but the said program gives an error. I have noticed that when files are downloaded in FireFox, they already appear in the Downloads folder with the corresponding file extension with 0 bytes and these are then apparently swapped or merged with the .parts file. The problem is that the mentioned program now tries to retrieve the unfinished file, which then leads to an error. Does anyone know if it is possible to customize Firefox so that the file only appears in the download folder when the download is fully complete? Many thanks for your help :D

All Replies (8)

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I don't think there is a way to avoid Firefox using the .part files, but you can set Firefox to use the system Temp folder for those and then move the file to your designated download folder at the end. This is how Firefox worked in Firefox 97 and earlier. (I assume your monitoring software doesn't try to do anything with the Temp folder.) This option is a bit hidden:

(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

Does that help?

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jscher2000 - Support Volunteer schrieb

I don't think there is a way to avoid Firefox using the .part files, but you can set Firefox to use the system Temp folder for those and then move the file to your designated download folder at the end. This is how Firefox worked in Firefox 97 and earlier. (I assume your monitoring software doesn't try to do anything with the Temp folder.) This option is a bit hidden: (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 Does that help?


Hi jscher2000,

thank you for your reply.

I have made the change but the behavior remains the same. Enclosed I have an example file in a screenshot in which the behavior can be seen.

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Are both of those files in the Temp folder now?

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jscher2000 - Support Volunteer schrieb

Are both of those files in the Temp folder now?

No, the files are still in the final Download Folder destination. I will check it again in more detail. I did not restart FireFox.

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jscher2000 - Support Volunteer schrieb

Are both of those files in the Temp folder now?

I have tested it again with the mentioned flag:

  • FireFox Rapid Release
  • FireFox ESR

Including browser restart

The download files & .parts files remain directly in the target download folder as shown in the screenshot above.

I suspect the flag has no effect anymore and fear that there is no other method :(

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It works in Chromium based browsers, but I would like to avoid using such browsers for privacy and seczurity reasons.

I suspect that Chromium handles the download differently here.

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It is possible that your security software is causing the problem. Try to disable security software temporarily to see if that makes a difference.

Boot the computer into Windows Safe Mode with network support to see if that has effect.

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I see what you mean. While you are selecting the folder and finalizing the name for the file -- with "Always ask you where to save files" selected -- Firefox is downloading to a .part file in the Temp folder, but as soon as you finalize your choice, the .part file and a placeholder file are moved to the final destination folder, which occurs before you are ready for that to happen when you are downloading a large file.

I don't recall whether the files were moved so quickly in Firefox 97 and earlier; it's been a while.