I got a new laptop and it came with a new version of Adobe Reader which showed a dialog window every time I open a pdf document with it. The contents of the dialog window was:
Reading Untagged Document
This 1-page document is untagged and must be prepared for reading. While the document is being analyzed, your assistive technology will not be able to interact with this application.
Reading Order Options …
Reading Mode Options …
It seems there are three ways of dealing with this dialog window, each with different pros and cons or costs:
1. Check the checkbox (recommended)
You can check the checkbox named “Always use the settings from the Reading Preferences (Do not show this dialog again)” and then press either Start or Cancel. This way is probably what the Adobe team wants you to do.
Pros: The dialog is never shown again.
Costs: It may slow down opening pdf files on slow computers. You can change the options (that was in the dialog) later from the Reading panel in Preferences.
2. Press Cancel each time
You could just press the Cancel button on the dialog every time. This is what those who are not tech savvy and wants no change to their PCs should do.
Pros: Nothing is changed, so nothing you don’t expect will happen.
Cons: Nothing is changed, so the dialog window will show up again and again.
3. Disable the related feature
Open Preferences and under the Accessibility panel, uncheck “Enable assistive technology support.” My googling showed up no result suggesting this way.
Pros: The dialog is never shown again and no slow down.
Costs: No assistive technology support.
I do not recommend disabling assistive technology support on public computers.