When I print in Acrobat it flattens every page and it takes a long time.

Try different settings of the scanner software.

Have you tried printing it directly from the file (e.g. using a USB -> PDF Direct)?

Somewhere along the way, transparency was introduced into your scanned file. What resolution was your PDF scanned as? One wouldn't assume there would be any transparent objects in a simple scan but if you also did OCR on the text, this tends to break up the scan into chunks of stitched complicated PDF layers of varying transparency especially if it attempts to straighten them. Also, if you have a high-resolution scan that's highly compressed, it needs to be UNcompressed at print stage; this takes time no matter what.

fyi, every file is flattened in some way at some point. With a printer/RIP with a built-in Adobe PDF Print Engine, it happens in the printer where it renders directly from the PDF code... which is the best, obviously; otherwise it's converted to PostScript or PCL depending on your installed options and driver, either way taking up your computer's time doing so.

Unless you have an external RIP, I don't see any evidence your machine has an APPE.

You could always try pre-flatten the file in Acrobat using PDF Optimizer. Use the Flattener Preview to identify what and where transparency is applied.

Hi @Chris2828839760rj 

Hope you are doing well and sorry to hear that.

What is the version of the Acrobat DC you are using? To check the version go to Help > About Acrobat and make sure you have the recent version 23.01.2006x installed. Go to Help > Check for updates and reboot the computer once.

Check for any missing/pending updates for printer drier and firmware and try updating it. You may also try to remove the Printer driver and firmware, reboot the computer and reinstall it from the manufacturer web site and see if that works.

Try to repair the installation from the help menu (Win Only) and see if that works. Also go to Edit (Win), Adobe Acorbat (Mac) > Preferences > Enhanced Security > Uncheck,  'Enable protected mode at startup.' > Click OK and reboot the computer.
Note: Please turn on the security after testing to avoid any security risk.

Please try to reset the Acrobat preferences as described here https://community.adobe.com/t5/acrobat-discussions/how-to-reset-acrobat-preference-settings-to-default/td-p/4792082 and go through the help page https://helpx.adobe.com/acrobat/kb/troubleshoot-pdf-printing-acrobat-reader.html 

You may also try to create a new test user profile with full admin rights in Win or enable the root account in MAC and try using the application there and check.

Regards

Amal