none
Blob and file download disabled in IE11 RRS feed

  • Question

  • Hi guys,

    We are having a problem with a customer that has File Downloads disabled for the internet zone but added our website into trusted websites (with file download enabled) and can't download files.

    Our files are sent received on a javascript fuction as blobs and we are using msSaveOrOpenBlob in the case of IE11 but no matter what we try, even if our website is on the Trusted Sites we always get "hello.txt couldn't be downloaded".

    The following is a quick and dirty sample of what we are doing. This works fine with file downloads enabled in the internet zone.

    var content = "Hello world";
    var filename = "hello.txt";
    var blob = new Blob([content], { type: "text/plain" });
    window.navigator.msSaveOrOpenBlob(blob, filename);

    TL;DR;

    We have a website with IE11 settings set to:

    Internet Zone -> File Download disabled.

    Trusted Sites -> File Download enabled.

    Out site is added to the Trusted Sites zone.

    With the function above we always get "hello.txt couldn't be downloaded", even though our website is on the Trusted Sites zone. If we enable file downloads on the internet zone this works just fine but for security reasons our customer can't do that.

    Any ideas?

    Thursday, September 28, 2017 1:02 PM

Answers

  • I had a similar question open, and Rob / IECustomizer shared a solution posted on a blog Feb 9th, which did the trick.

    in short: Add the word

    blob

    as a trusted site.

    I would provide the link but i'm not verified so I cannot. I wonder if I will ever receive that verification email...

    • Proposed as answer by JMS.JR Tuesday, April 10, 2018 6:11 PM
    • Marked as answer by pbessone Tuesday, June 5, 2018 11:21 AM
    Tuesday, February 27, 2018 10:14 PM

All replies

  • Hi,

    f12>Emulation tab, will tell you which IE Emulation mode is being used and how it was established. eg. Enterprise Mode, Enterprise site mode lists, (user Compatibility View list etc). IE11 needs to be using IE10 emulation or higher to support blobs.

    f12>Debug tab, select "Break on all exceptions" from the drop down, then without closing the dev tool (PIN it to the browser)... start debugging your website (place breakpoints in your code where the blob is called).

    Regards.

    Questions regarding Internet Explorer 8, 9 and 10 and Internet Explorer 11 for the IT Pro Audience. Topics covered are: Installation, Deployment, Configuration, Security, Group Policy, Management questions. To avoid confusion please post links to any website(s) you are having problems with your questions. Post web page coding questions to stackoverflow.


    Rob^_^

    Sunday, October 1, 2017 10:49 PM
  • Hi Rob,

    Thank you for your response but sadly this doesn't help us solve the issue.

    Our site is not running on compatibility mode (so its running full IE11). There are no errors nor exceptions on the console or the debugger, either handled or unhandled.

    The javascript code above is a minimal example that can reproduce the issue without any server side interaction. On our real website when debugging we can see the blob is accepted and downloaded by the client without any problems, the issue is with the msSaveOrOpenBlob function and that sadly is outside our reach.

    As soon as we call msSaveOrOpenBlob we get the open, save/save ass or cancel dialog and when we click on either save or save as, immediately we get "{filename} couldn't be downloaded" message. Again, no errors on the console.


    • Edited by pbessone Monday, October 2, 2017 8:27 AM
    Monday, October 2, 2017 8:26 AM
  • Hi,

    try

    Tools>Internet Options>Advanced tab, uncheck "Do not save encrypted files to disk"

    Post questions about web site programming (coding) to the appropriate MSDN forum and if possible include a link to a jsfiddle mashup (or your website) that is reproducible.

    Regards.

    Questions regarding Internet Explorer 8, 9 and 10 and Internet Explorer 11 for the IT Pro Audience. Topics covered are: Installation, Deployment, Configuration, Security, Group Policy, Management questions. To avoid confusion please post links to any website(s) you are having problems with your questions. Post web page coding questions to stackoverflow.


    Rob^_^

    Monday, October 2, 2017 8:59 PM
  • Hi Rob,

    Its not that simple. The question is not about programming, its a potential bug in IE.

    We managed to escalate this issue with Microsoft themselves and they are investigating.

    From what we were able to determine yesterday after talking with someone from Microsoft, whenever you try to save blob data to disk, IE considers it a Low Integrity process operation and hence it uses the Internet Zone settings rather than the Trusted Sites Zone settings.

    The expected behaviour is that when a website is on the Trusted Sites zone, all operations for that site should be governed by the Trusted Sites settings but this is not the case for blobs.

    As I said, Microsoft is investigating and I hope the come back with a hotfix or a workaround for the issue because it affects hundreds of our customers.

    I'll update this thread when we have more news.

    Regards


    • Edited by pbessone Tuesday, October 3, 2017 8:34 AM
    Tuesday, October 3, 2017 8:24 AM
  • Hi there, did you get any further with this issue?

    We have the same issue for an internally developed app;

    Internet zone - downloads disabled
    Trusted zone - downloads enabled
    Intranet zone - downloads enabled

    Yet, for this particular site which uses the blob function - if we try to download a table of csv data we get "couldn't download csvname.csv".  No errors in any of the debuggers, if we set IE11 back to default config then it seems to work but I suspect this is because internet zone file downloads becomes enabled which for us, is not a fix.

    Thanks

    Monday, October 23, 2017 8:50 AM
  • Hello! I am having the very same issue on my side, have you found a solution as of yet? I'm stumped.

    Stopped downloads in internet zone.

    added sites to trusted sites

    Download starts, then says "couldn't be downloaded"

    Thank you!

    Wednesday, February 14, 2018 9:39 PM
  • Use the Networking tab of the dev tool to inspect the content length of the download response.

    An internal (intranet site) is likely to be using code behind (asp.net) to return the response of the download request. use response.close(), not response.flush() when your stream reaches eof.

    To assist you in debugging web pages on your dev/test machine first go Tools>Internet Options>Advanced tab, check "Always record developer console messages"

    ..... where to post programming questions...

    Regards.


    Rob^_^

    Wednesday, February 14, 2018 10:15 PM
  • I had a similar question open, and Rob / IECustomizer shared a solution posted on a blog Feb 9th, which did the trick.

    in short: Add the word

    blob

    as a trusted site.

    I would provide the link but i'm not verified so I cannot. I wonder if I will ever receive that verification email...

    • Proposed as answer by JMS.JR Tuesday, April 10, 2018 6:11 PM
    • Marked as answer by pbessone Tuesday, June 5, 2018 11:21 AM
    Tuesday, February 27, 2018 10:14 PM
  • This is exactly what we ended up doing.

    We spent about a month on coming and goings with Microsoft support and this is what they finally suggested we do.

    Sadly with Internet Explorer not being actively developed (except for security patches) since 2016 this is never going to be properly addressed and the solution IMHO is more of a hack than a proper fix :(

    Tuesday, June 5, 2018 11:27 AM
  • https://  blogs.msdn.microsoft.com/askie/2018/02/09/how-to-enable-blob-downloads-in-ie-through-in-trusted-sites/
    Tuesday, October 2, 2018 1:46 PM