Up until the newest batch of updates for Pro I could export multiple or single PDFs with a predetermined name from a map series. To do this I would export the layout as a PDF with a blank filename, simply naming the file location '...User/Desktop/.pdf' Then under the map series tab select export as 'Multiple Files (Page name as suffix)'. This would create any pages I needed using the name as it appears on the map series. This saved me from manually entering in or editing 600+ file names.
Now when I attempt this, I get an error stating "The location does not exist or is an invalid path." I guess I could enter in an arbitrary letter or digit and then use PowerShell to remove this from all of the filenames. Why would they take away this simple feature? Are there any workarounds that you use to complete a similar workflow?
I'm having the same issue as well. It's baffling that they don't just have a 'Page name as file name' option. What is the benefit of removing this feature?