The Reader Extensions are special certificates applied to a pdf files either via Adobe Acrobat or LiveCycle Reader Extensions server.
They allow Reader to use functions (saving, commenting, attachments etc.) for this files which generally or only allowed to Arobat.
The message you get for example occurs if the file was damaged and Reader restored it to display it correctly.
This causes the Reader Extensions to become invalid.
Also possible is that the used Reader has some flaws and needs to be updated.
Thanks for the reply!
So when I am designing the form in LCD its not a property under setting/form [properties that I can set to force the extension? Or are there additional settings I should be choosing under the LCD form properties that will minimize the possibility of Reader having issue with it.
This one has been a strange one to figure out because its delivered via Acrobat.com and all people open the same form from Acrobat.com - and only a few [different] sites have the error.
Reader Extension can ONLY be added by Acrobat or LiveCycle Reader Extensions Server!
Designer doesn't have such function.
The problem you have may not have to do with any further setting in Designer.
It can be a problem when downloading the forms from Acrobat.com to the local hard drive or the Reader is faulty.
You can try to distribute the form via mail instaed of Acrobat.com.
If the problem is gone, you know the downloading is the problem, otherwise it may be the Reader that is used.