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What's an application/octet-stream and why does Firefox want me to open or save it?

Posted

I had just updated Firefox, I opened up Google, googled something and entered into the first webpage that came up- or tried to. What I got was a box from Firefox saying:

You have chosen to open the file

(URL of the webpage)

which is an application/octet-stream What would you like to do with this file?

          []Open With...   [Browse] (as a button)
          []Save As...
                           [Ok]              [Cancel]

This happens with every webpage that isn't from Google or Mozilla. If I hit Cancel, the webpage won't load, if I select Save As, no program I have can open it and if I select Open With, same situation. So... what gives? What's an application/octet-stream? Why won't Firefox open webpages apart from Google or Mozilla pages (my previous version of Firefox worked fine)?

Modified by trekkie

Additional System Details

This happened

Every time Firefox opened

This started when...

I updated Firefox to its current version and attempted to open a webpage not mentioned above as OK

Installed Plug-ins

  • Shockwave Flash 10.0 r32
  • Office Plugin for Netscape Navigator
  • 6.0.12.709
  • RealPlayer(tm) LiveConnect-Enabled Plug-In
  • RealJukebox Netscape Plugin
  • The QuickTime Plugin allows you to view a wide variety of multimedia content in Web pages. For more information, visit the QuickTime Web site.
  • NPRuntime Script Plug-in Library for Java(TM) Deploy
  • Default Plug-in
  • Unity Player 2.6.1f3
  • Adobe Shockwave for Director Netscape plug-in, version 11.5
  • iTunes Detector Plug-in
  • Next Generation Java Plug-in 1.6.0_21 for Mozilla browsers
  • 4.0.50524.0
  • Office Live Update v1.5
  • NPWLPG
  • Windows Presentation Foundation (WPF) plug-in for Mozilla browsers
  • Google Update
  • Npdsplay dll
  • DRM Store Netscape Plugin
  • DRM Netscape Network Object

Application

  • User Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-GB; rv:1.9.2.8) Gecko/20100722 Firefox/3.6.8 (.NET CLR 1.1.4322; .NET CLR 2.0.50727; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729)

More Information

Application Basics
Name
Firefox
Version
3.6.8
Profile Directory
Open Containing Folder
Installed Plugins
about:plugins
Build Configuration
about:buildconfig
Extensions
Name
Version
Enabled
ID
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true
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Java Console
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{CAFEEFAC-0016-0000-0017-ABCDEFFEDCBA}
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jqs@sun.com
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{66E978CD-981F-47DF-AC42-E3CF417C1467}
RealPlayer Browser Record Plugin
1.0
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{ABDE892B-13A8-4d1b-88E6-365A6E755758}
Adblock Plus
1.2.1
true
{d10d0bf8-f5b5-c8b4-a8b2-2b9879e08c5d}
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QuickDrag
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quickdrag@mozilla.ktechcomputing.com
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{9AA46F4F-4DC7-4c06-97AF-5035170634FE}
AlertCheck
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alertcheck@mike.conley
AlertStopper
100.001
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alertstopper@dorian.meric
Check All
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checkall023@extensions.hesslow.se
CheckFox
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{BAEC7B80-9A31-47b2-A68B-DCAC8DF48E87}
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Currency Converter
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{af5514fc-7603-4cec-9894-f07f3d8672a5}
Copy Link Text
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copylinktext@brett.zamir
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{078fac48-925f-4524-7cfe-85d44b8f4f98}
EAVE
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eave@grbradt.org
Expiry Canary
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Fasterfox
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{c36177c0-224a-11da-8cd6-0800200c9a91}
Flash Killer
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flashkiller@joli.clic
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firefox@ghostery.com
Gmail Notifier
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{44d0a1b4-9c90-4f86-ac92-8680b5d6549e}
Gmail Popup
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gmailpopup@gmailnotreally.com
Gmail Watcher
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gmailwatcher@sonthakit
Google Date
0.1.3.1
true
kiyotaka1022@gmail.com
GoogleEnhancer
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{21e48e29-f574-4619-b65d-0f00eea92e5b}
InvisibleHand
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canitbecheaper@trafficbroker.co.uk
Keyboard Shortcuts
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keyshort@eric.hamiter
Kongregate Sidebar
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true
kongregate@captaincaveman.nl
Link Alert
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linkalert.conlan@addons.mozilla.com
Link And Forminfo
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{B71ACFF2-E436-4cc7-B5E3-0C8E2CC981BA}
LinkExtend
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{cf47767d-5f3a-4e32-9fce-5d79565c9702}
Override Mozilla Firefox Guidance
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omfg@olive
PingMe
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pingme@arcticfire
Privacy Plus
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Read Later
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RightToClick
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{cd617375-6743-4ee8-bac4-fbf10f35729e}
SimilarWeb
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Simple Links Counter
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simplelinkscounter@extensiondevelopment.org
Site Information Tool
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siteinfo@wmtips
Tab Progress Bar
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tabprogressbar@studio17.wordpress.com
Test Extension
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testext@savetheworld.org
TimeStamp Converter
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tsconverter@sogame.cat
Trustpilot Guard
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Verify Redirect
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wappalyzer@crunchlabz.com
WeatherBug
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Java Console
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Personas
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personas@christopher.beard
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Sidebar Companion for Google Sidewiki
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Java Console
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Java Console
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Ask Toolbar
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Value
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true
browser.history_expire_days.mirror
180
browser.places.importBookmarksHTML
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browser.places.smartBookmarksVersion
2
browser.startup.homepage
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rv:1.9.2.8
extensions.lastAppVersion
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general.useragent.extra.betterprivacy
general.useragent.extra.microsoftdotnet
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network.http.pipelining.firstrequest
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network.protocol-handler.app.magnet
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places.last_vacuum
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cor-el
  • Top 10 Contributor
  • Moderator
10751 solutions 96760 answers

application/octet-stream is a generic content (MIME) type. Firefox will always show the "open with" download dialog if a server sends a file with such a MIME type. You shouldn't get that MIME type with every web page that you open. You may have security software (firewall) that has changed the original content type.

A possible cause is security software (firewall) that blocks or restricts Firefox without informing you about that, possibly after detecting changes (update) to the Firefox program.
Remove all rules for Firefox from the permissions list in the firewall and let your firewall ask again for permission to get full unrestricted access to internet for Firefox and the plugin-container process.

See Server Not Found - Troubleshoot connection problems and Configure firewalls so that Firefox can access the Internet and http://kb.mozillazine.org/Firewalls

wewerwqerweqr 0 solutions 4 answers

That's because the zealots at firefox like to harass the end users.

If you instead use Internet Explorer, you can just check that it should always save the file instead of annoying the user like Firefox wants to do (they refuse to fix this problem)

the-edmeister
  • Top 10 Contributor
  • Moderator
3196 solutions 24401 answers

The developers consider it a security issue.

Question owner

The problem seems to have gone away by itself. Thing is, I still don't know what caused it in the first place (cor-el, nothing I did to my firewall fixed the problem), so it could pop up again at any time.

ghickers 0 solutions 1 answers

I am getting the message on the Royal Caribbean Website. This is occurring on the page where the 360 Tour of the Stateroom is located.

No suitable plugins were found.

      Unknown Plugin (application/octet-stream) 

This only happens with Firefox not IE or Safari. I'm getting this error every time I go to this page. I have upgraded Firefox several times since I first noticed this error with no changes.

mlglz 0 solutions 1 answers

Try disable Adblock Plus

ProfMaryT 0 solutions 1 answers

Silly games to be played Save the file. Go to the FireFox pulldown menu top left corner, choose Downloads. Select the file that you saved and and click on Launch (top left). Often that will make the document open in the original format.

If that doesn't work, try this. Click on Save, go to the saved file on your hard drive, select it and right click on Rename and add whatever extension you need. For example when Firefox stops what I know is an Excel 2007 file from a student, I just rename it like this: Joestats.xlsx. Then the renamed file will open normally in Excel 2007 just like Joe sent it to me.

oldhippierick 0 solutions 3 answers

Here's how I get around the mess with this application/octet-stream files. I save as WinRar when that comes up at download. And to open once DL'ed I right click open then it opens all apps that you have on file. Pick WinRar and click open to then extract to were you want files to be held.. hope it helped..

mtfrancis 0 solutions 1 answers

I tried opening a unknown file that was described as an application.octet-stream with OpenOffice and it worked just fine. Hope this helps others.