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Windows is configured to block legacy file system filters RRS feed

  • Question

  • Hi,

    We are testing our File System filter driver for the Windows 10 RS3 (1709) upgrading to RS4 and found that our driver was blocked by Windows with following error message in Event Viewer.

    Windows is configured to block legacy file system filters

    Our legacy file system filter driver was blocked after upgrade Windows 10 from RS3 to RS4.

    We found a registry settings that relate to this error described at: https://docs.microsoft.com/en-us/windows-hardware/drivers/ifs/blocking-file-system-filter-drivers

    According to that page, the default value of IoBlockLegacyFsFilters is 0, which means legacy file system driver will not block by Windows.

    • Windows 10 RS4 17623 Insider Preview

    But our testing results show that after upgrade Windows 10 RS3 to RS4, our file system filter driver, which have not port to Filter Manager yet, was blocked.

    And seems like the last boot after RS3 to RS4, the IoBlockLegacyFsFilters has no effect. Reboot again, the legacy file system driver is not blocked. We are confused of the behavior.


    A C++ developer.

    Sunday, March 18, 2018 3:34 PM

Answers

  • Hello Sam:

    First of all, I'd like to calm you down regarding the next Windows 10 RS4 release. We have seen the same problem with the very same registry key and value in old products.

    It seems that the upgrade process to RS4 was made without that registry key, provoking the legacy filter block you have seen. Only by performing a reboot, after the upgrade process had been done was the moment that key was being included. So, effectively it wasn't working cause the problem is in the upgrade process itself. The customer affected would have to reboot the computer once and then reinstall your product again, bearing in mind they could be affected in different ways by that blockade.

    The good news I said before is that this "block legacy filter" policy seems to have been freshly removed from RS4 release and postponed to RS5. If your company has certain partnership with Microsoft and you have access to internal builds, which I assume you can, you should see that the latest Windows 10 RS4 build 17123 allows you to perform the upgrade process flawlessly. Focus on these versions numbered 171XX right now, because the build you mention, 17623 (or 176XX line) is a Windows 10 RS5 candidate (the next version release is scheduled for Autumn 2018 right now). As I said this RS5 will have the legacy filter blockade active as Microsoft has specified, but right now your product should be installed on RS4 or upgraded to it perfectly.

    Hope this helps.

    Regards.


    • Edited by AGH1981 Monday, March 19, 2018 12:49 PM
    • Marked as answer by Sam Tsai (I3D) Monday, March 19, 2018 3:34 PM
    Monday, March 19, 2018 12:48 PM

All replies

  • Hello Sam:

    First of all, I'd like to calm you down regarding the next Windows 10 RS4 release. We have seen the same problem with the very same registry key and value in old products.

    It seems that the upgrade process to RS4 was made without that registry key, provoking the legacy filter block you have seen. Only by performing a reboot, after the upgrade process had been done was the moment that key was being included. So, effectively it wasn't working cause the problem is in the upgrade process itself. The customer affected would have to reboot the computer once and then reinstall your product again, bearing in mind they could be affected in different ways by that blockade.

    The good news I said before is that this "block legacy filter" policy seems to have been freshly removed from RS4 release and postponed to RS5. If your company has certain partnership with Microsoft and you have access to internal builds, which I assume you can, you should see that the latest Windows 10 RS4 build 17123 allows you to perform the upgrade process flawlessly. Focus on these versions numbered 171XX right now, because the build you mention, 17623 (or 176XX line) is a Windows 10 RS5 candidate (the next version release is scheduled for Autumn 2018 right now). As I said this RS5 will have the legacy filter blockade active as Microsoft has specified, but right now your product should be installed on RS4 or upgraded to it perfectly.

    Hope this helps.

    Regards.


    • Edited by AGH1981 Monday, March 19, 2018 12:49 PM
    • Marked as answer by Sam Tsai (I3D) Monday, March 19, 2018 3:34 PM
    Monday, March 19, 2018 12:48 PM
  • Hello AGH1981,

    Thanks for the reply.

    I can confirm that 17123 build work flawlessly as you stated. Greatly help us on this one. Thank you!

    You mentioned that Microsoft decided to "block legacy filter" in RS5, could you provide the link or place where Microsoft made the announcement? It would be better for us and our client to plan the upgrading to RS5 scenario even though it will be released 6 months later.

    Thank you very much!


    A C++ developer.

    Monday, March 19, 2018 3:40 PM
  • Hello again Sam:

    Glad to here it worked for you. And as you say, you've won as many time as 6 months for your next move.

    I haven't seen a link I can share where Microsoft tells widely they're going to block legacy filters in RS5, but if your company has access to MS Collaborate in the new Developers Portal, you will be able to find information and also presentations where this block operation is assured for Autumn 2018 version. All doc shares there are confidential, so I can't tell or share anything else.

    But if you have access, then browse for Redstone 4 Meet Call presentations from November or December 2017, and you'll be able to see the related info for yourself.

    RS4 version up to now has been a warning for legacy filter operations not to be used anymore. Next Windows 10 RS5 is scheduled to be the end of life for them.

    Regards.

    Monday, March 19, 2018 5:38 PM
  • Hi,

    We are testing our File System filter driver for the Windows 10 RS3 (1709) upgrading to RS4 and found that our driver was blocked by Windows with following error message in Event Viewer.

    Windows is configured to block legacy file system filters

    Our legacy file system filter driver was blocked after upgrade Windows 10 from RS3 to RS4.

    We found a registry settings that relate to this error described at: https://docs.microsoft.com/en-us/windows-hardware/drivers/ifs/blocking-file-system-filter-drivers

    According to that page, the default value of IoBlockLegacyFsFilters is 0, which means legacy file system driver will not block by Windows.

    • Windows 10 RS4 17623 Insider Preview

    But our testing results show that after upgrade Windows 10 RS3 to RS4, our file system filter driver, which have not port to Filter Manager yet, was blocked.

    And seems like the last boot after RS3 to RS4, the IoBlockLegacyFsFilters has no effect. Reboot again, the legacy file system driver is not blocked. We are confused of the behavior.


    A C++ developer.

    Just FYI. This problem has been report on Windows 10 Feedback Hub: https://aka.ms/M3chi2


    A C++ developer.

    Wednesday, March 21, 2018 10:47 AM
  • FYR. We tested a new build 17627 and found that the IoBlockLegacyFsFilters no longer added and the legacy file system driver NOT blocked anymore. Looks like Microsoft do change their policy for legacy file system driver.

    A C++ developer.

    Thursday, March 22, 2018 5:20 PM