A custom plug-in loads in "Acrobat Reader DC" and after 2-3 seconds the Reader says
"Invalid plug-in detected and reader would close"
The same plug-in is working fine when using "Adobe Acrobat"
So the difference is ("Adobe Acrobat") and
(All Readers = ("Acrobat Reader DC and Adobe Reader X and Adobe reader 10"))
Have you created the plugin or is this a third-party plugin?
It is the BasicPlugin from the SDK. I build it usng VS 2013.
And it is working perfect when loaded in the "Adobe Acrobat"
But all the READERS are detecting it as invalid plugin.
Yes, this is as designed, and as documented in the SDK. You need to use Acrobat Pro or Acrobat Standard to develop your plug-in. When it is developed, you can apply to Adobe to pay for a license for a Reader plug-in. They look at your proposal, and give a price, which could be as high as $25,000 per year. Then you get the key needed to "Reader enable" the plug-in.