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Opera empties the FEATURE_BROWSER_EMULATION registry key on updates/reinstall

  • I've been wondering for weeks why my FEATURE_BROWSER_EMULATION registry key keeps emptying itself. This registry keys is used by other software to select the internet explorer version when embedding the internet explorer activex control. Now when I reinstall opera (and I guess it is the same for updates), this key is emptied, and other software does not work correctly. How can that be?

    1. Check the content of the following registry key:
      Computer\HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_BROWSER_EMULATION
      There should be a list of programs in there including browser_assistant.exe. (If browser_assistant.exe is the only item in there, then add some fake entries for reproducing this issue).

    2. In the windows settings Apps&Features select to uninstall Opera. When it ask if you want to reinstall, choose that option.

    3. Check the registry key again: Computer\HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_BROWSER_EMULATION
      All that is left in there is browser_assistant.exe.

    Opera Version:72.0.3815.400
    Windows 10 1909 x64

  • @benjykid
    Seems totally wrong behavior to me. Does this happen with Chrome or Edge installation too?
    I think you should send bug report to Opera team.

  • I haven't checked Chrome and Edge yet, but I will when their next update is installed. The browser_assistant.exe entry ("C:\Program Files (x86)\Internet\Opera\assistant\browser_assistant.exe") that always remains in there made me suspect opera as the culprit.

  • @benjykid
    Do you use that assistant? I hopefully got rid of it many months ago, although looking at registry, browser_assistant entry is present on pointed key here too. I personally have no need for changing IE (control) emulation level, thereby I had not noticed that.

  • I have no idea what browser_assistant.exe is good for. But it it is in the run registry key, so it runs at startup.

    I'm getting bug reports that websites in my application are not displaying correctly. And then I find that this registry key got deleted.

  • Reported as bug DNAWIZ-120881.

  • @benjykid said in Opera empties the FEATURE_BROWSER_EMULATION registry key on updates/reinstall:

    I have no idea what browser_assistant.exe is good for. But it it is in the run registry key, so it runs at startup.

    If you have no idea, then likely you could remove it from run key (and from task scheduler and other places; I personally deleted entire opera assistant folder too).

    I'm getting bug reports that websites in my application are not displaying correctly. And then I find that this registry key got deleted.

    You could just re-insert your required key at start of your application. We once considered that, but fortunately our app (or rather rarely used part of it) could work with older IE compatibility level and thereby we have no direct experience with it.