Cannot open .xlsb attachment.

[ojboss123]

As title, I cannot open an .xlsb attachment via Acrobat Reader.

I have scoured the web and found a 'fix' by editing the tBuiltInPermList reg key at HKLM\SOFTWARE\Policies\Adobe\Acrobat Reader\DC\FeatureLockDown\cDefaultLaunchAttachmentPerms to add the problematic file extensions.

Unfortunately this has had no effect and there doesn't appear to be any answers to this out there other than 'this is expected' or 'by design'.

Any suggestions on this would be greatly appreciated.

[Test Screen Name]

Do you mean this is an XLSB attachment inside a PDF that is open in Reader?

What happens?

[ojboss123]

Correct.

It errors stating Acrobat cannot open due to PDF attachment security settings