Why am I getting an error message when trying to combine files into one PDF file?

Hello Markb,

We apologize for the inconvenience caused, as per the description above, you are not able to combine PDF files on Mac machine using Acrobat Pro DC, is that correct?

I have checked the records with your current Adobe ID(email) which you have used to sign-in on Adobe forums and found that the subscription of Acrobat Pro DC is canceled and inactive.

You can also check the details of your plan through Adobe.com>Manage Account>Plans and Products, or you can also refer to the Adobe article Manage your Creative Cloud membership

This is the reason you are getting the error message while combining any PDF files as you don't have any active subscription/license if Acrobat. To access the services, you have to subscribe to Acrobat license/subscription.

For plans and pricing, you can refer to Plans and pricing | Adobe Acrobat DC You can also contact Adobe support for the plans and pricing and to place a new order Contact Customer Care

Feel free to update this discussion for any further assistance.

Regards,

Anand Sri.