Internet explorer ignores flash mms.cfg settings

user_1129986 0
Viewed 12887

I have the following mms.cfg in

  • %localappdata%\Google\Chrome\User Data\Default\Pepper Data\Shockwave Flash\System\mms.cfg
  • %localappdata%\Microsoft\Edge\User Data\Default\Pepper Data\Shockwave Flash\System\mms.cfg
  • %windir%System32\Macromed\Flash\mms.cfg
  • %windir%\SysWOW64\Macromed\Flash\mms.cfg
EOLUninstallDisable=1
SilentAutoUpdateEnable=0
EnableAllowList=1
AutoUpdateDisable=0
AllowListUrlPattern=http://localhost/flash/
ErrorReportingEnable=1
EnableInsecureLocalWithFileSystem=1

With this after I set my PC date to something in 2021. I'm able to run Flash in

  • Chrome - Which uses the config in %localappdata%\Google\Chrome\User Data\Default\Pepper Data\Shockwave Flash\System\mms.cfg
  • Edge Chromium - Which uses the config in %localappdata%\Microsoft\Edge\User Data\Default\Pepper Data\Shockwave Flash\System\mms.cfg
  • Firefox - %windir%System32\Macromed\Flash\mms.cfg

Based on my understanding IE11 should be using the one from %windir%System32\Macromed\Flash\mms.cfg but for whatever reason it seems like it's ignoring it and the settings in this file have no effect and flash is still disabled. enter image description here

Just to be on the 100% sure that IE uses that config file I've ran ProcMon and it seems like IE is actually opening the file as you can see in the picture. enter image description here

My question is why is internet explorer ignoring this? And what can I do about it? Other useful info:

  • Firefox and Chromium browsers use 32.0.0.433
  • IE11 uses 32.0.0.387 which is the windows embedded version of flash.
  • Tested on
    • Windows 10 Pro 10.0.18362
    • Windows 10 Pro 10.0.19041
    • Windows 10 Home 10.0.18362
  • I took Flash player version 32.0.0.330 from an older version of Windows and I didn't even get the EOL behavior. This leads me to believe that this is a FP version issue and that version 32.0.0.387 which is distributed by MS might not support AllowListUrlPattern.

Things I've tried and didn't work include:

  • Restarting the machine
  • Setting the encoding of the .cfg to UTF-8.
internet-explorer-11 windows-10 internet-explorer flash windows
3 Answers

I tested this on Windows 10 Enterprise 10.0.19041 and Flash Player 32.0.0.387 with same results.

I then ran Windows updates which installed Flash Player 32.0.0.445. https://support.microsoft.com/en-us/help/4580325/security-update

This version respected mms.cfg settings as expected.

My mms.cfg was placed in %windir%\SysWOW64\Macromed\Flash and %windir%\System32\Macromed\Flash

and it looks like this:

EOLUninstallDisable=1
EnableAllowList=1
AllowListUrlPattern=*://*.mydomain.com/
AllowListUrlPattern=*://localhost/
AllowListUrlPattern=*://localhost:5311/

Also, having played around with different dates I've determined the cut off date to be 01/12/2021.

user_1631760
user_62982750

I was having the same problem in IE 11 and found the answer at the this page.

In short, using the EnableWhitelist, WhitelistPreview, WhitelistUrlPattern flags instead of EnableAllowList, AllowListPreview, AllowListUrlPattern in the mms.cfg file worked for me.

My mms.cfg file is in below path:

C:\Windows\SysWOW64\Macromed\Flash

Thanks

user_147640240
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