When Acrobat is not set as the default PDF handler and it is launched, a dialog prompts whether to make Adobe Acrobat the default PDF application.
You can select the Do not show this message again check box to suppress the message.
Once the check box is selected, a registry key corresponding to it is preferred and is created at the registry path as follows:
DWORD: iAppDoNotTakePDFOwnershipAtLaunch which is set to value 1
**If AVAlert or cCheckbox do not exist by default, then select the Do not show this message again check box on the dialog box and then recheck.
For Windows 10, the name of the DWORD is iAppDoNotTakePDFOwnershipAtLaunchWin10
Possible values of this registry key are:
1: Do not show this message again
0: Show this message every time Acrobat is launched until it is set as the default PDF handler.
You can create the key manually or use it using deployment to suppress the message.