The operation failed because Adobe Acrobat encountered an unknown error in Mac

I also faced this while updating a document, what i did is I saved the pdf using print within the adobe acrobat application, selected 'microsoft print to pdf' as printer, and then the saved copy was editable.

Hi @pachara5D19 

Hope you are doing well.

As per the issue description that Acrobat shows the error in the fill and sign tool. Please check for any pending updates of Acrobat or Reader you are using to use the Fill&Sign feature from help>check for updates, reboot the machine after installing the updates, and see if this brings any difference.

Try signing the PDF using the URL https://cloud.acrobat.com/fillsign on a browser like Chrome or Firefox, or Safari, and see if you still get the error message.

Also, If you are using Acrobat or Reader, Launch Acrobat/Reader>click Edit>Preferences>under Security (Enhanced).

Uncheck the box next to Enable Protected Mode at startup > click OK > relaunch Reader and try again.

Note: Disabling protected mode is for troubleshooting purpose only. Please turn the feature back on when troubleshooting is complete.

Let us know how it goes and share your findings.

Regards,

Harsh.