impossible d'effectuer l'opération en raison d'une erreur indéterminée ONSF

Hi there

Hope you are doing well and thanks for reaching out.

When Adobe Acrobat displays an "impossible to perform the operation due to an undetermined ONSF error," it usually means there's a problem with the underlying file structure or security settings within the PDF document, often caused by corrupted data, complex formatting, or incompatible features that Acrobat can't process properly.

Also, your AI file is quite large due to the high-quality photos, which is likely to be another reason causing the errors when exporting to PDF. Please try to adjust the PDF preset setting in Illustrator , also try to export the file in small parts and see if that works.

For Acrobat, make sure you have the latest version 24.05.2039X installed. Go to Help > Check for updates and reboot the computer once.

For testing purposes, you may try to turn off the protected mode, Go to Preferences (Ctrl,Cmd+K) > Enhanced Security > uncheck 'Enable Protected mode at startup' and turn off the protected mode and reboot the computer once. 
Note: Please tun on the protected mode after testing to avoid any security risk.

Let us know how it goes.