Can't install Preflight in Acrobat Pro v.25

Acrobat itself has the ability to create PDF/A files, through Acrobat Distiller. You may want to try this workflow and see if it works for you:

• Go to your Creative Cloud application. Choose the File>Print menu command.
• In the Printer: options box, select PostScript® File. Click the Save button.
• Here's where your Windows system will try to slip you a mickey. The Filename: edit box will want to name your file [filename].indd.ps. you want to delete the .indd file suffix out of the middle of the file name, so it reads [filename].ps. Double suffixes in Windows file names are fraught with peril.

• Open Acrobat Distiller.
• In the Default Settings: options box, choose one of the PDF/A options, as shown above.
• Go to the File>Open menu command, and navigate your way to your .ps file. Click the Open button, and Distiller will use that Postscript print-to-file to create your PDF/A file. When you open it, you'll see the banner above that says it claims compliance with PDF/A, as shown below. The file ain't lyin'.
• Don't click the Enable Editing button though, or it will no longer be a PDF/A formatted file. It's for archive; it's not for changing or updating.

It's a bit of a rigamarole, but it works. For what it's worth, way back in the PageMaker days. This was the way you had to make PDF files. For the most part, that's not the case today — except for this case.

Hope this helps,

Randy