10.13.6 problems while opening (double click) JPG, PDF, (and more..?)

[maurizios]

Hi everybody,
all of a sudden with my iMac mid 2011 High Sierra 10.13.6 if I try to open by double clicking on them JPG and PDF files issues the message "[file name] is damaged and can't be opened. You should move it to the Trash".
All the files are actually good in fact if I open them with Preview (my default for JPG) or Acrobat Reader (default for PDF) they are all ok.
This problem affects all the users of the iMac.
Apparently Office files are fine, i.e. they can be open by double clicking on them.
One strange thing that maybe is meaningful: if I create a JPG (e.g. by a screenshot) I can open it by double clicking on it only the first time, meaning that if I close it and try to open it again then I constantly get the error.
SOS disk and starting in safe mode did not help.

Thank you in advance for your help.

Maurizio

 

[Taz Mangus]

The first thing to try is downloading the full High-Sierra installer, run it and have it install on top of your current install. It won't erase any user data, only refresh the OS system files.

‎macOS High Sierra

‎New technologies at the heart of the system make your Mac more reliable, capable, and responsive — and lay the foundation for future innovations. macOS High Sierra also refines the features and apps you use every day. It’s macOS at its highest level yet. Easily organize, edit and view your...

apps.apple.com

If that does not work then maybe the link below will help. If that does not work, since you stated it affects all the user accounts, then maybe you want to consider doing a backup, erase and install of High Sierra and migrate user data from backup.

file "is damaged and can't be opened" when opening twice a mounted file

I have a mounted directory to access some images. When opening an image for the first time with open /mounted_dir/foo.jpg it opens the image in preview. When repeating the same command it gives the

stackoverflow.com

 

[maurizios]

Crossing fingers, the problem seems to be solved .. spontaneously!!

As suggested, I decided to install High Sierra on top of my current install and therefore prepared a Time Machine backup .. just in case .. that took a few hours to complete. When Time Machine finished, Preview, Acrobat .. seemed to work fine again.
I see no reasons to believe the backup solved this, but I really changed nothing with respect to the previous attempts.
Though what is available in the Net is about apps and not files as in my case, some users said it could a matter of permission (Gatekeeper) and therefore I may conclude that this sudden change back to normality could have been somethow related to the antivirus (I have Sophos Home and I did not turned it off during my attempts) that in this period received some upgrade or fix.
Just guessing, anyway, but hopefully now everything is fine.

Thank you again to everybody - and a special thank to Taz Mangus - for your help.
Regards

Maurizio

 

[Taz Mangus]

You are very welcome. Glad it is working again for you.