Error message "File is already compressed" when trying to compress PDF in Adobe Acrobat

I use a computer that I am unable to install external software on. I have the same problem with Adobe Acrobat Web not wanting to effectively compress PDFs.

My workaround is to open the PDF and then Print to PDF from there. You can reduce the page size if you really want to shave off MBs, but generally just pushing it through a new PDF printer will do quite effective compression.

My iPhone scans come out ridiculously large so I have to do this to reduce the size to something normal.

I hope this workaround helps.

Sorry for the late reply. You say you have not uploaded a compressed file, are you are able to compress a file that you have not yet uploaded? If so, where are you uploading the file? It's possible compression is applied to the file after uploading. The PDF/X standard prohibits certain types of compression, try saving the downloaded pdf as PDF/X-4 (File> Save as other> PDF/X> Settings), then try to compress. I assume you are using the Optimizer tool to apply your compression, if PDF/X does not help, try removing the compression with the optimizer tool (see attached screen shot), also try the optimizer setting "Make compatible with: Acrobat 8.0 and later". If you are still having issues, try the preflight check or fixup also shown on the screen shot. Tools> Print production> Preflight.

Hi there

Hope you are doing well and sorry for the delay.

Is this an issue with a particular PDF file or with all the PDFs? Please try with a different PDF file and check.

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 24.01.20604 installed. Go to Help > Check for updates and reboot the computer once.
 
Also try to repair the installation from the help menu (Win Only) and see if that works.

Let us know how it goes.

~Amal