I've successfully exported book PDF in the past, but now Export command is grayed out unless I open a single InDesign file within my INDD book file.
If I open ALL files in by book file, I can Export, but only the single file that is selected from within the browser window of all opened files.
If I hold down shift key a select all the INDD files in my book file (which is what I've done in the past), export command is still grayed out.
If I open my book file and highlight one of the INDD files within it without opening that file, export command is still grayed out.
What can I do to fix problem so I can export book to PDF?
I've quit application and reopened holding down Control, Option, Command and Shift keys in order to delete and rebuild Preferences file, but that hasn't fixed problem.