Hello raymondpTEX
We apologize for the inconvenience caused, as per the description above, you are not able to print any PDF file as getting an error message Can’t open “/private/var/spool/cups/tmp/0612f5a6ft27f, Is that correct?
Please check for any pending updates of Adobe Reader(if any) from Help>Check for updates and reboot the machine.
You can also reset the preferences of Adobe Reader, refer to How to reset Acrobat Preference settings to default.
Reboot the machine after resetting the preferences.
Make sure that the latest printer driver is installed. You can try to print the PDF as image, refer to Print PDF as image | Adobe Acrobat, Reader
You can refer to the following KB dc Troubleshoot PDF printing in Acrobat and Reader
If the issue persists, please use Adobe cleaner tool to remove the Adobe Reader Download Adobe Reader and Acrobat Cleaner Tool - Adobe Labs
Reboot the machine and install the Adobe Reader back from Adobe - Adobe Acrobat Reader DC Distribution
Please share the following details:
Let us know how it goes.
Regards,
Anand Sri.